f United States 

Environmental Protection 
LmI #m Agency 


LIBRARY OF CONGRESS 

MLCM 

2006/02667 

F J tlEQDE 
GenCoii 


Draft Protocol for Measuring 
Children's Non-Occupational 
Exposure to Pesticides by all 
Relevant Pathways 



i 







EPA/600/R-03/026 
September 2001 


Draft Protocol for Measuring Children’s 
Non-Occupational Exposure to Pesticides by 

all Relevant Pathways 

by 

Maurice R. Berry, Elaine A. Cohen Hubal, Roy C. Fortmann, Lisa J.Melnyk, 

Linda S. Sheldon, Daniel M. Stout II, Nicolle S. Tulve, and Donald A. Whitaker 
Human Exposure and Atmospheric Sciences Division 
National Exposure Research Laboratory 
Research Triangle Park, NC 27711 
and 

Microbiological and Chemical Exposure Assessment Research Division 
National Exposure Research Laboratory 
Cincinnati, OH 45268 


Contract nos. 68-D-99-011 and 68-D-99-012 
Ellen Streib, Project Officer 
Human Exposure and Atmospheric Sciences Division 
National Exposure Research Laboratory 
Research Triangle Park, NC 27711 


National Exposure Research Laboratory 
Office of Research and Development 
U.S. Environmental Protection Agency 
Research Triangle Park, NC 27711 



Recycled/Recyclable 
Printed with vegetable-based ink on 
paper that contains a minimum of 
50% post-consumer fiber content 
processed chlorine free. 


LIBRARY of congress 

ML CM 

2006/02667 

Notice 

The U.S. Environmental Protection Agency through its Office of Research and 
Development funded and managed the research described here under Contract Number 68-D-99- 
011 to Battelle and Contract number 68-D-99-012 to RTI International. It has been subjected to 
the Agency’s peer and administrative review and has been approved for publication as an EPA 
document. 

Mention of trade names or commercial products does not constitute endorsement or 
recommendation for use. 


\ 

LC Control Number 



2003 628608 




















Abstract 


In support of the Food Quality Protection Act (FQPA) of 1996, research is being 
conducted by the U.S. EPA National Exposure Research Laboratory to develop methods, data, 
and models for evaluating children’s aggregate exposure to pesticides by all relevant pathways. 
The FQPA requires the EPA to use exposure assessments in the pesticide tolerance setting 
process. The exposure assessments must consider the aggregate exposures of infants and 
children from all sources (food, water, soil, dust, and air) and routes (inhalation, dermal 
exposure, indirect ingestion, and dietary ingestion). FQPA requires that risk assessments must be 
based on exposure data that are of high quality and high quantity or exposure models using 
factors that are based on existing, reliable data. Currently, the data on children’s exposures and 
exposure factors are limited and generally not adequate to assess residential exposures to 
consumer products and environmental contaminants. Several general areas of research are 
needed to improve the quality and quantity of data available for exposure assessments for 
children. Appropriate age and developmental benchmarks for categorizing children in exposure 
assessments must be identified. The activity pattern data for children (especially very young 
children) required to assess exposure by all routes need to be developed. Methods for measuring 
children’s exposures need to be developed and improved. Finally, field studies are needed to 
develop distributions of exposure and associated exposure factors. 

The goal of this document is to provide guidance for generating data that can be used to 
improve exposure assessments for young children, as required by FQPA. Currently, standard 
protocols for conducting exposure field studies that provide data for measurement-based 
exposure assessments do not exist. Likewise, protocols for developing exposure factor data to be 
used for modeling assessments are not available. Although research on children’s exposure to 
pesticides and other toxic chemicals is being performed within EPA, academia, industry, and 
other research organizations, protocols that have been developed by individual researchers for 
specific studies do not always collect all of the data required for reliable exposure assessments, 
and the data collected cannot always be interpreted. 

The draft protocol provides approaches and methods that can be used for conducting field 
studies to collect exposure measurement data and to develop exposure factors. The protocol first 
provides a framework for conducting measurement studies for aggregate exposure assessments 
then describes the algorithms developed to assess exposure by each route. The algorithms are 
used to determine a priori what data must be collected in field studies to quantify exposure; the 
protocol provides explicit data requirements for each route of exposure. The approaches for 
estimating exposure by each route are described and include discussions of the data requirements, 
general considerations related to data collection, measurement methods, collection of activity 
pattern information, and exposure factors. The use of activity diaries and questionnaires is 
discussed for each route of exposure. The use of biomonitoring data is also discussed. 

This report covers the period from January 1999 to September 2001. 


in 










































































































Contents 


Abstract .iii 

Figures. vii 

Tables.viii 

Acknowledgment.ix 

1.0 INTRODUCTION.1 

1.1 Background .1 

1.2 Purpose.2 

1.3 Scope.3 

1.4 Format of the Document . 4 

2.0 BASIC CONCEPTS OF AGGREGATE EXPOSURE.5 

2.1 Definitions.5 

2.2 Measurement Methods Versus Approaches.5 

2.3 Exposure Assessment.8 

2.4 Framework for Exposure Assessment.9 

3.0 EXPOSURE ALGORITHMS AND DATA REQUIREMENTS .15 

3.1 Exposure Algorithms.15 

3.2 Inhalation Route.16 

3.3 Dermal Route.19 

3.3.1 Macroactivity Approach.20 

3.3.2 Microactivity Approach.21 

3.4 Ingestion Route .23 

3.4.1 Dietary Ingestion .25 

3.4.2 Indirect Ingestion.26 

4.0 EXPOSURE SCENARIO .31 

5.0 APPROACH FOR ESTIMATING INHALATION EXPOSURE.35 

5.1 Introduction .35 

5.2 Summary of Data Requirements .35 

5.3 General Considerations .35 

5.4 Monitoring and Sampling Methods.37 

5.5 Exposure Factor/Activity Pattern Information.40 

5.6 Estimation of Inhalation Rates.42 

6.0 MACRO ACTIVITY APPROACH FOR ESTIMATING DERMAL EXPOSURE .... 46 

6.1 Introduction.46 


v 


































6.2 Summary of Data Requirements .46 

6.3 General Considerations .46 

6.4 Monitoring Methods .49 

6.5 Exposure Factor/Questionnaire Information.54 

6.6 Estimation of Transfer Coefficients.54 

7.0 APPROACH FOR ESTIMATING DIETARY INGESTION EXPOSURE .57 

7.1 Introduction.57 

7.2 Summary of Data Requirements .58 

7.3 General Considerations .58 

7.4 Monitoring Method .59 

7.5 Exposure Factor Information.60 

8.0 APPROACH FOR ESTIMATING INDIRECT INGESTION EXPOSURE.62 

8.1 Introduction.62 

8.2 Summary of Data Requirements .62 

8.3 General Considerations .63 

8.4 Monitoring Methods .64 

8.5 Exposure Factor Information.67 

9.0 OTHER DATA COLLECTION . 72 

9.1. Questionnaire Data To Identify Sources and Usage of Pesticides in Residences 

and Daycares .72 

9.1.1 Introduction.72 

9.1.2 Administering Questionnaires.72 

9.1.3. Information on Sources to be Collected in Pesticide Exposure 

Measurement Studies.73 

9.1.4 Information on Microenvironment Surfaces, the Structure and the 

Occupants.77 

9.1.5 Additional Data Collection for SHEDS-Pesticide Model.77 

10.0 REFERENCES .79 

APPENDIX A - Description of the ORD/NERL Stochastic Human Exposure and Dose 
Simulation Model for Pesticides (SHEDS-Pesticides) 

APPENDIX B - Food Diary and Questionnaires 


vi 



























Figures 


Figure 2-1. Conceptual model of children’s residential exposure to pesticides.10 

Figure 3-1. Conceptual model of pesticide exposure by the ingestion route.24 

Figure 5-1. Example of one page of the Indoors at Home section of a 24-h time-activity diary 
for estimating inhalation and dermal exposure of young children.41 

Figure 8-1. Examples of data required for assessing indirect ingestion exposure and sample 

questions.68 

Figure 8-2. Examples of questions included in the NERL Hygiene and Dietary Habit Survey 
(included in Appendix B).70 


Figure 9-1. Example questions use to collect information on pesticide usage in a residence. 74 
Figure 9-2. Questions on occupational exposure to pesticides.76 


Vll 








Tables 


Table 2-1. Definitions Related to Aggregate Exposure Assessments.6 

Table 2-2. Pathways for Children’s Non-Occupational Exposure to Pesticides.12 

Table 3-1. Summary of Data Collection Requirements by Exposure Route.18 

Table 4-1. Scenario for Protocol Development.31 

Table 4-2. Relevant Age-Related Developments (From U.S. EPA, 2000b).32 

Table 4-3. Behavioral Age Bins (From U.S. EPA, 2000b).33 

Table 5-1. Data Requirements for Estimating Inhalation Exposure Route.36 

Table 5-2. Ranges of Inhalation Rates (g) for “Normal” Female Children and Adolescents on 

a per Body Mass Basis by Generalized Type of Activity (L min' 1 kg' 1 ).43 

Table 5-3. Ranges of Inhalation Rates (g) for “Normal” Male Children and Adolescents on a 
per Body Mass Basis by Generalized Type of Activity (L min' 1 kg' 1 ) .44 

Table 6-1. Data Requirements for Estimating Dermal Exposure With the Macroactivity 

Approach.47 


Table 6-2. Microenvironment/Macroactivity Combinations for Estimating Dermal Exposure 
.48 

Table 6-3. Microenvironments/Macroactivity Combinations and Surfaces for Which Activity 


Data Are Collected.55 

Table 7-1. Data Requirements for Estimating Dietary Ingestion Exposure .58 

Table 7-2. Method Detection Limits and Pesticide Recoveries 3 from Medium Fat Composite 
Diet Samples Fortified at 1, 5 and 10 ng/g.61 

Table 8-1. Data Requirements for Estimating Indirect Ingestion Exposure.63 


Vlll 

















Acknowledgment 


The authors would like to thank Dr. Valerie Zartarian and Dr. Thomas McCurdy of the 
U.S. Environmental Protection Agency for their contributions to the protocol. The authors also 
wish to acknowledge the contributions of Ross Highsmith, Dr. Daniel Vallero, and other staff in 
the Human Exposure and Atmospheric Sciences Division who have been involved in the work 
on the Human Exposure Measurements - Children’s Focus research program. 


IX 













I- 











































































1.0 


INTRODUCTION 


1.1 Background 

The U.S. Environmental Protection Agency (U.S. EPA) has pledged to increase its efforts 
to provide a safe and healthy environment for children by ensuring that all EPA regulations, 
standards, policies, and risk assessments take into account special childhood vulnerabilities to 
environmental toxicants. 

In evaluating environmental health risks to children, it is important to understand that 
children are not little adults. Children’s exposures to environmental contaminants and consumer 
products are expected to be different and, in many cases, much higher than older individuals. 
These differences in exposure are due to differences in physiological function and surface to 
volume ratio. Children’s behavior and the way that they interact with their environment may 
have a profound effect on the magnitude of their chemical exposures. Children crawl, roll, and 
climb over contaminated surfaces, resulting in higher dermal contact than would be experienced 
by adults in the same environment. Children’s mouthing activities (hand-to-mouth and object-to- 
mouth) will result in indirect ingestion of chemicals if the hands or objects are contaminated. 
Increased indirect ingestion of contaminants also occurs when children handle and eat foods that 
have come in contact with the floor or other contaminated surfaces. 

In order to articulate the problems and research needs associated with children’s exposure 
to environmental pollutants, the EPA Office of Research and Development (ORD) developed the 
Strategy for Research on Environmental Risks to Children (U.S. EPA, 2000a). This strategy is 
centered on the child with the overall goal of improving risk assessments for children and 
reducing those risks. Within the Children’s Risk Strategy three specific objectives have been 
formulated to (1) make use of existing information to develop improved risk assessment methods 
and models for children; (2) design and conduct research on exposure, effects, and dose-response 
that will answer questions about age-related differences in exposure and risks and that will lead 
to better risk assessments for children; and (3) explore opportunities for prevention and reduction 
of risks to children. 

ORD also conducts research related to children’s exposure in support of the Food Quality 
Protection Act (FQPA) of 1996. FQPA requires EPA to upgrade the risk assessment procedures 
for setting pesticide residue tolerances in food by considering the potential susceptibility of 
infants and children to both aggregate and cumulative exposures to pesticides. Aggregate 
exposures include exposures from all sources, routes and pathways for individual pesticides. 
Cumulative exposures include aggregate exposures to multiple pesticides with the same mode of 
action for toxicity. Very importantly, FQPA requires that risk assessments must be based on 
exposure data that are of high quality and high quantity or exposure models using factors that are 
based on existing, reliable data. 


1 


Currently, the data on children’s exposures and exposure factors are limited and generally 
not adequate to assess residential exposures to consumer products and environmental 
contaminants. Several general areas of research are needed to improve the quality and quantity 
of data available for exposure assessments for children. Appropriate age/developmental 
benchmarks for categorizing children in exposure assessments must be identified. The activity 
pattern data for children (especially young children) required to assess exposure by all routes 
need to be developed. Methods for measuring children’s exposures need to be developed and 
improved. Finally, field studies are needed to develop distributions of exposure and associated 
exposure factors. 

The Children’s Exposure Research Program at the EPA National Exposure Research 
Laboratory (NERL) is designed to meet several of the above research needs. Research in support 
of FQPA has been conducted to: (1) identify those pathways and activities that represent the 
highest potential exposures; (2) determine the factors that influence exposures; (3) develop 
approaches and methods for measuring and assessing aggregate exposures that account for 
children’s activities; (4) develop distributional data on aggregate exposures; and (5) generate data 
on multimedia pesticide concentrations, pesticide biomarkers, and exposure factors that can be 
used as inputs to aggregate exposure models for exposure assessment. 

1.2 Purpose 

The overall goal of this document is to provide guidance for generating data that can be 
used to improve exposure assessments for young children, as required by FQPA. Typically, 
exposure assessments are conducted using either a measurement-based approach or a modeling- 
based approach. Data requirements for both types of assessments are addressed in this document. 

Exposure assessments for FQPA must consider pesticide exposures of infants and 
children from all sources and all potential exposure media, including those from food, water, 
dust, soil, and air. The definition of a complete and reliable data set for pesticide exposures of 
children was provided in Exposure Data Requirements for Assessing Risks from Pesticides 
Exposure of Children (U.S. EPA, 1999a). As specified in that document, an exposure 
assessment should include the following four elements: 

1. An initial screening-level exposure assessment to identify all important sources and 
pathways of exposure for the pesticide. 

2. An initial assessment to identify the age groups that are at the greatest risk from aggregate 
pesticide exposures. 

3. Protocols for measuring exposure for all relevant pathways and age groups. Protocols 
should include: 

• the algorithms for combining the environmental monitoring data with exposure 
factor data to estimate an exposure, 

• a description of the environmental media that should be measured, 


2 


• standard methods for measuring pesticides in those environmental media, 

• a description of the activity patterns and exposure factors required, and 

• methods for collecting data for all of the relevant activity pattern and exposure 
factors. 

4. An aggregate exposure assessment using probabilistic multimedia, multipathway models 

to develop population exposure distributions. 

Currently, standard protocols for conducting exposure field studies that provide data for 
measurement-based exposure assessments (element 3) do not exist. Likewise, protocols for 
developing exposure factor data to be used for modeling assessments are not available. Although 
research on children’s exposure to pesticides and other toxic chemicals is being performed within 
EPA, academia, industry, and other research organizations, protocols that have been developed 
by individual researchers for specific studies do not always collect all of the data required for 
reliable exposure assessments, and the data collected cannot always be interpreted. 

The purpose of this document is to address element 3, as described above. This 
document is a draft protocol that provides approaches and methods that can be used for: (1) 
conducting field studies to collect exposure data, (2) developing exposure factor data, and (3) 
interpreting data to estimate exposure. 

The methods, measurements, and modeling research conducted by NERL in support of 
FQPA serves as the basis for this document. The focus of this document is to provide a draft 
protocol for measuring aggregate exposures for children from residential uses of pesticides 
and/or for collecting data on exposure factors. However, the document is also intended to 
provide basic insights into data requirements and approaches for assessing children’s aggregate 
and cumulative exposure and may be generalized to many environmental pollutants. 

1.3 Scope 

This document presents a draft protocol for measuring children’s exposure to pesticides 
by all relevant pathways. It addresses approaches and methods for measurements of children’s 
exposure that can be used as part of field monitoring studies. The protocol describes the 
algorithms for each route of exposure, specifies the data required to conduct the aggregate 
exposure assessment, and describes methods for collecting the data. The approach is provided 
for estimating exposure by each route. References are provided to assist the reader in obtaining 
detailed information on the utility of measurement methods, procurement of materials and 
supplies, and implementation in the field. 

There are a number of elements of an exposure measurement study that are not addressed 
in this protocol because they are specific to the study objectives and study design and are beyond 
the scope of this document. For example, this document does not discuss sample selection and 
participant recruitment. The survey design is a critical, and very complex, element of any 


3 


exposure study, but discussion of this study element is beyond the scope of this document. The 
protocol also does not address screening methods that may be used to identify potentially highly 
exposed sub-populations or environments. Because the methods in the protocol should be 
applicable to a wide range of pesticides and to selected environmental contaminants with a 
variety of analytical requirements, analytical methods are not discussed in the protocol. The user 
of the protocol will need to identify and use the appropriate analytical methods to measure the 
compounds of interest after collection. 

This is a draft protocol that does not specify the detailed methods to be used for data 
collection. A number of research studies are on-going or planned that will be used to further 
evaluate the protocol, data collection methods, and questionnaires to be used in future children’s 
exposure measurement studies. Results of these studies will be used to refine the protocol and to 
develop detailed specifications for approaches and methods. 

1.4 Format of the Document 

The document is organized to provide general information on exposure and a modeling 
framework for addressing children’s exposure. Information is given on the algorithms and 
methods for collecting data on exposure and exposure factors. Specific sections are as follows: 

• Section 2 discusses the basic concepts of exposure including definitions. It also provides 
a framework for conducting measurement studies for aggregate exposure assessments. 

• Section 3 gives proposed exposure algorithms along with explicit data requirements for 
each route of exposure. 

• Section 4 describes the exposure scenario addressed by this draft protocol. 

• Sections 5 through 8 describes approaches for measuring exposure by various routes and 
pathways. 

• Section 9 discusses other data collection methods including questionnaires. 

• Section 10 includes references cited in the document. 


4 


2.0 BASIC CONCEPTS OF AGGREGATE EXPOSURE 


The purpose of this chapter is to first define the concepts of exposure. The reader is then 
introduced to the basic framework that NERL has been using to develop a protocol that defines 
both approaches and methods for measuring exposure and exposure factors in field studies. 

2.1 Definitions 

Exposure is defined as the contact (at visible external boundaries) of an individual with a 
pollutant for specific durations of time. For exposure to occur, environmental media must be 
contaminated with a pollutant, an individual must be in the same microenvironment with the 
contaminated media, s/he must come in contact with a contaminated medium, and the contact 
activity must cause a transfer of the contaminant from the media to the portal of entry of the 
individual. 

Children’s exposure to environmental contaminants is a complex process that may occur 
from several sources through a number of different pathways and routes. Sources include all 
uses of a chemical that could result in children’s exposure. Within this document, only 
nonoccupational exposures to environmental contaminants are considered. Route of exposure 
(i.e., dermal, oral, inhalation) is defined as the portal of entry. There are three routes of 
exposure: the skin is the portal of entry for the dermal exposure route; the mouth is the portal of 
entry for the ingestion exposure route, and the lung is the portal of entry for the inhalation 
exposure route. Pathway is defined as the course that the contaminant takes from its source to 
the portal of entry. In some cases, we have simplified the pathways to only include the 
contaminated exposure media and route of exposure. Exposure pathways include those that 
occur indoors and outdoors at the home and at other institutional and non-residential settings 
(e.g., schools and daycare centers). Aggregate exposure is the combined exposures to a single 
chemical from all sources across all routes and pathways. 

Exposure Factors are the factors related to human behavior and characteristics that 
determine an individual’s exposure to a pesticide or contaminant. For example, an individual’s 
exposure to a pesticide by the inhalation route is determined by factors that include the duration 
of time spent in different microenvironments during the day and the individual’s inhalation rates 
during the period of exposure. 

Other definitions used in this document that are pertinent to conducting aggregate 
exposure assessments are given in Table 2-1. 

2.2 Measurement Methods Versus Approaches 

Traditionally, exposure measurement studies have been based on using a set of methods 
to measure contaminants in environmental media. Questionnaires and diaries are then used to 


5 


Table 2-1. Definitions Related to Aggregate Exposure Assessments 


Term 

Definition 

Acute exposure 

An exposure period of less than one day. 

Aggregate exposure 

The combined exposures to a single chemical from all sources across 
all routes and pathways. 

Approach 

The process for combining data from single determinants to estimate 
exposure. 

Biomarker of 
exposure 

Exogenous chemicals, metabolites, or the products of interactions 
between a chemical and target molecules or cells that are measured 
within a compartment or within an organism. This includes internal 
dosimeters of a chemical or metabolite concentrations and markers of 
biologically effective doses. 

Chronic exposure 

An exposure presumed to occur over a substantial portion of the 
individual’s lifetime. 

Cumulative 

exposure 

The total exposure to chemicals that cause a common toxic effect(s) to 
human health by the same, or similar, sequence of major biochemical 
events. 

Exposure 

The contact (at visible external boundaries) of an individual with a 
pollutant for specific durations of time. 

Exposure algorithm 

A mathematical expression of the approach. It expresses exposure as a 
function of pesticide concentration in the exposure medium, contact 
rate, rate of transfer from the exposure medium to the portal of entry, 
and exposure duration. 

Exposure factors 

The factors related to human behavior and characteristics that 
determine an individual’s exposure to a pesticide or contaminant. For 
example, duration of exposure, inhalation rates, transfer coefficients. 

Exposure pathway 

The course that the chemical takes from its source to the receptor’s 
portal of entry. 

Exposure route 

The portal of entry of a chemical into the body. 

Exposure scenario 

The combination of facts, assumptions, and inferences that define a 
discrete situation or activity where potential exposures may occur. 

These include the source, the exposed population, the time frame of 
exposure, microenvironment(s), and activities. 


6 


















Term 

Definition 

Intermediate-term 

exposure 

An exposure lasting from one week to several months. 

Macroactivity 

Aggregated series of contact events in the same microenvironment and 
the same activity level. 

Method 

A process for measuring a single determinant such as an environmental 
concentration of a pesticide or an activity frequency. 

Microactivity 

Individual skin-to-surface or object-to-mouth contact event. 

Microenvironment 

A space or location defined for dermal exposure on the basis of 
specific surface types that may be contacted (e.g., indoors at home on 
carpet). For inhalation exposure, it is defined as an air space with a 
homogenous concentration of the chemical. 

Pathway 

The course that the contaminant takes from its source to the portal of 
entry. 

Short-term exposure 

An exposure lasting from one to seven days. 

Transfer coefficient 

A measure of contaminant transfer resulting from contact of an object 
or skin with a contaminated microenvironmental surface while engaged 
in a specific macroactivity, expressed as surface contact area per unit 
time (cm 2 /h). 

Transfer efficiency 

The fraction of mass transferred from a contaminated surface to skin, 
food, or other object per unit contact (unitless). 

Transferable surface 
residue 

The mass of contaminant per unit area (pg/cm 2 ) measured by a 
standard transfer method. 

Total surface 
loading 

The total mass of contaminant per unit area (pg/cm 2 ). 


collect information on activities and locations. Often a systematic selection of methods and 
questions is not developed and the resulting data cannot be used to estimate exposure by multiple 
routes and pathways. Within this document, the emphasis is on the use of approaches to estimate 
exposure rather than the application of a set of methods. Such a process first determines how 
exposure for each route will be estimated, then defines the data needed, and finally identifies 
specific methods for data collection. 


7 















Within this protocol, a method is defined as a process for measuring a single determinant 
such as an environmental concentration of a pesticide or an activity frequency. An approach 
defines the process for combining data from single determinates to estimate exposure. The 
exposure algorithm defines the approach. For each route, the algorithm mathematically 
expresses exposure as a function of pesticide concentration in the exposure medium, contact rate, 
rate of transfer from the exposure medium to the portal of entry, and exposure duration. 
Consequently, the exposure algorithm describes the specific data needs for estimating exposure 
and the process for combining the data. This protocol describes both methods for the single 
determinants and the algorithms for estimating exposure by each pathway and route. 

2.3 Exposure Assessment 

Typically, exposure assessments are conducted using either an individual measurement- 
based approach or a population modeling-based approach. For simplicity, these will be referred 
to as measurement and modeling assessments throughout this document. Data requirements and 
measurement study designs will vary for the two approaches. This document emphasizes data 
collection methods and approaches for measurement-based assessments. 

Measurement assessments measure the contact of the individual with the chemical in 
the exposure media over an identified period of time. Direct assessments are made through field 
monitoring studies of children in their everyday environments. In such studies, data are collected 
on pollutant concentrations in a variety of exposure media (i.e., air, drinking water, food, house 
dust, surface residues), activities, and exposure factors so that exposure can be measured or 
estimated for each child in the study. Often pesticides or their metabolites are analyzed in 
biological media as a direct measure of exposure aggregated over all sources and pathways for a 
given time period. A comparison of exposure estimated from measurement assessments to 
exposure estimated with biomarkers often provides a evaluation of both approaches. For 
measurement assessments, it is imperative to collect all of the data on exposure media 
concentrations, activities, and exposure factors that are required to quantify exposure for an 
individual using the exposure algorithms for each route and pathway. 

Modeling assessments use available information on concentrations of chemicals in 
exposure media along with information about when, where, and how individuals might contact 
the exposure media. The modeling approach then uses models and a series of exposure factors 
(i.e., contact duration, contact frequency, contaminant transfer) to estimate exposure. For 
modeling assessments, distributional data on exposure factors and environmental concentrations 
are used to estimate exposure distributions for a population. However, the data do not need to be 
collected on the same individuals. For the modeling approach, studies can be conducted to 
obtain data for only a single exposure factor or a combination of exposure factors. No attempt is 
made to actually measure or estimate exposure for the individual participants in the study with 
the modeling approach. Data on activities and exposure factors collected as part of a 
measurement assessment can also be applied to modeling assessments. 


8 


2.4 Framework for Exposure Assessment 


Aggregate exposure includes exposure from all sources, routes and pathways for 
individual pesticides. Given this definition, a comprehensive approach is required to understand 
and adequately address all of the components of an aggregate exposure assessment. NERL has 
developed a framework to systematically identify the important sources, routes, and pathways for 
exposure (Cohen Hubal et al., 2000). This framework is based upon the development of a 
conceptual model for aggregate exposure and provides the basis for developing a protocol to 
measure and assess aggregate exposures, as well as for developing sophisticated stochastic 
models. This framework also allows us to systematically identify the most critical research needs 
and data gaps associated with children’s exposures to pesticides. The steps of the framework are 
as follows: 

1. Develop a model that describes aggregate exposure, 

2. Identify potential exposure pathways and scenarios, 

3. Define algorithms, exposure factors, and data requirements for each route, 

4. Develop a probabilistic model for assessing aggregate exposure, 

5. Perform a screening assessment to evaluate the range of exposures for, and significance 
of, each pathway, 

6. Identify critical data gaps in the assessment process, and 

7. Conduct field studies to address data gaps and reduce uncertainty. 

Steps 1 through 3 have been critical in the development of this protocol. Steps 4, 5, and 6 have 
been used to identify research needs. The protocol developed here will be applied to studies in 
step 7. 


Although the emphasis of this protocol is on measuring and assessing residential pesticide 
exposure to infants and young children, this same framework could be adapted for other 
exposure scenarios. 

Model. A conceptual model of children’s residential exposure to pesticides was 
developed by NERL that was the initial focal point for the research strategy and protocol 
development. This conceptual model (Figure 2-1) shows the exposure process from source to 
absorbed dose for all routes of exposure. Pesticides may be released into the outdoor or indoor 
environment by residential, commercial, or agricultural use. Once released into the environment, 
pesticides can transfer from one medium to another (e.g., air to soil) and from one micro¬ 
environment to another (e.g., yard to house). Exposure occurs once a human contacts a 
contaminated exposure medium and the contaminant is transferred from the medium to the portal 
of entry. Exposure is a function of the time spent in the microenvironment of interest, contact 
rate, and the mass transfer of pesticide from the exposure medium to the portal of entry. 

Contacts rates and mass transfer are a function of human activity patterns (indicated by the 
shaded ovals). Finally, uptake of the pesticide through the respiratory tract, the skin, or the 


9 


Figure 2-1. Conceptual model of children’s residential exposure to pesticides. 




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gastrointestinal tract will result in an absorbed dose. 

Exposure Pathways. The conceptual model was used to systematically identify all 
potential exposure pathways. In general terms, a pathway is defined as the course that a pesticide 
takes from its source to the receptor’s portal of entry. However to specifically evaluate potential 
for exposure, simplified pathways were defined by the exposure medium and the route of 
exposure. Essentially, the evaluation focused on exposure, without considering transport of the 
pesticide to the exposure medium. Using this simplified definition, the pathway crosses the 
activity with the exposure medium that leads to exposure. For example, inhalation (activity) of 
indoor air (exposure medium) is one pathway, and dermal contact (activity) with turf (exposure 
medium) is another pathway. A comprehensive list of potential pathways was developed and is 
presented in Table 2-2. 

Exposure Algorithms. Algorithms were developed to assess exposure by each route. 

The algorithm mathematically expresses exposure as a function of pesticide concentration in the 
exposure medium and various exposure factors, including contact rate, rate of transfer from the 
exposure medium to the portal of entry, and exposure duration. As described in Section 3, 
exposure algorithms are also used to describe the data requirements for each route in field 
monitoring studies to assess exposure using the measurement-based approach. 

Time Frame for Exposure Measurements. Risk assessments must take into account 
the frequency and duration of exposure, as well as its magnitude. In pesticide risk assessments, 
four exposure durations generally are considered. Acute exposure is defined as an exposure 
period of less than one day. Exposures through food and drinking water have been included in 
acute exposure assessments. Short-term exposure is defined as an exposure lasting from one to 
seven days. Possible short-term exposures to pesticides in and around the home could come 
from uses such as on lawns and home gardens, as a crack and crevice treatment for 
insects, a treatment for carpets or other surfaces, or a flea treatment for pets. Other short-term 
exposures could occur in public places such as parks, school playgrounds, and playing fields. 

Data indicate that post-application exposures from these uses typically last from a day to several 
weeks. Intermediate-term exposure is defined from one week to several months. Possible 
intermediate-term exposures to pesticides in and around the home could occur due to use of 
rodenticides as well as some of the exposure scenarios described above in the acute and short¬ 
term categories. Chronic exposure is presumed to occur over a substantial portion of the 
individual's lifetime. Although chronic exposure can occur via all routes and pathways, dietary is 
considered to be the largest component. Pesticides, such as those used as termite control, could 
also result in chronic exposures. 

Exposure Scenarios. For any given pathway, a set of associated exposure scenarios can 
be described. An exposure scenario is defined by the combination of: 

• Source or application method (e.g., crack and crevice application of pesticides, residential 


11 


Table 2-2: Pathways For Children’s Non-occupational Exposure to Pesticides 


Exposure Medium 

Route 

OUTDOOR PATHWAYS 

Pesticide pellets and 
granules 

Ingestion (direct) 

Dermal contact 

Ingestion (hand-to-mouth) 

Outdoor air 

Inhalation 

Dermal contact 

Ingestion of particles 

Outdoor water 

a) natural water body 

b) swimming pool 

Dietary ingestion 

Dermal contact (e.g.,while swimming) 

Ingestion (direct e.g., while swimming) 

Inhalation of vapors (e.g., while swimming) 

Soil 

Ingestion (direct) 

Indirect ingestion (object-to-mouth, hand-to-mouth) 

Dermal contact 

Plants 

a) turf 

b) gardens 

c) fruit on trees 

Ingestion (direct) 

Indirect ingestion (object-to-mouth) 

Dermal contact 

Indirect ingestion (hand-to-mouth) 

Outdoor surfaces/objects 

a) paint chips 

b) concrete 

c) toys, furniture, tools, etc. 

Indirect ingestion (object-to-mouth) 

Dermal contact 

Indirect ingestion (hand-to-mouth) 

INDOOR PATHWAYS 

Indoor air 

Inhalation 

Dermal contact 

Ingestion of particles 

Indoor water 

Dietary ingestion 


12 


































Exposure Medium 

Route 


Dermal contact (e.g., showering) 

Inhalation of vapors (e.g., showers, dishwashers, etc.) 

Food 

Dietary ingestion (food contaminated with agricultural residues) 

Indirect ingestion (food contaminated by contact with contaminated 
residential surfaces) 

Indirect ingestion (food contaminated by contact with contaminated 
hands) 

Indoor objects/surfaces: 

a) carpeted surfaces 

b) hard surfaces 

c) upholstery and bedding 

d) toys 

Indirect ingestion (object-to-mouth) 

Dermal contact 

Indirect ingestion (hand-to-mouth) 

House dust 

(Includes tracked in soil) 

Ingestion (direct) 

Indirect ingestion (object-to-mouth, hand-to-mouth) 

Dermal contact 

OTHER PATHWAYS 

Pets 

Dermal contact 

Indirect ingestion (hand-to-mouth) 

Material impregnated with 
pesticides 

Dermal contact 

Indirect ingestion (hand-to-mouth) 

Indirect ingestion (object-to-mouth) 

Inhalation of vapors 

Clothes 

I 

Dermal contact 

■ - 

Indirect ingestion (hand-to-mouth) 

Indirect ingestion (object-to-mouth) 


✓ 


13 




























use of consumer product, lawn and garden applications, agricultural use), 

• Exposed population (e.g., age group, geographical location), 

• Time frame of exposure (acute, short term, chronic), Microenvironments for exposure, 

and 

• Activity that results in exposure. 

When exposure assessments are conducted by the modeling approach, specific exposure 
scenarios determine the values of the exposure factors that should be used in the algorithms to 
estimate exposures. For measurement assessments, field studies are conducted to assess 
exposure for individual participants. For these studies, the participants actually define the 
scenario based on their everyday activities. Field studies can be conducted on a general 
population to understand distributions of exposures and exposure factors and the relationship 
between various exposure factors. These studies can also provide information to determine what 
scenarios actually exist in the population and to aid in selecting the most appropriate scenarios 
for modeling assessments. Alternately, studies can be conducted to evaluate exposure and 
exposure factors for predefined scenarios. In either case, it is necessary to collect all of the data 
that are needed to adequately define the scenario and the exposure factors that are used in the 
algorithm for that scenario. 

NERL has used the conceptual model discussed here to develop the Stochastic Human 
Exposure and Dose Simulation Model for Pesticides (SHEDS-Pesticides). SHEDS is a 
probabilistic multi-media, multi-pathway model (Zartarian et. al, 2000) that is designed to 
develop probability distributions of exposure and to also estimate inter-individual variability in 
the population and uncertainty in the estimated empirical exposure and dose distributions. The 
model is described in Appendix A of this document. Measurement data collected with the 
protocol described in this document will be used as inputs and for evaluation of the SHEDS- 
Pesticides model. Results of the sensitivity and uncertainty analyses conducted with SHEDS- 
Pesticides will be used to further refine the protocol for the exposure measurements. Hence, 
SHEDS-Pesticides will be used in an iterative fashion with the conceptual framework presented 
here to refine the protocol. 


14 


3.0 EXPOSURE ALGORITHMS AND DATA REQUIREMENTS 


The purpose of this chapter is to present the exposure algorithms that have been 
developed for assessing exposure by each route and pathway. The data requirements associated 
with the algorithms are also given. Details of the methods to collect these data are presented in 
subsequent chapters. 

3.1 Exposure Algorithms 

Exposure algorithms have been developed to assess exposure by each route. The 
algorithms are used here to determine a priori what data must be collected in field studies to 
quantify exposure. Thus, the algorithms provide a convenient framework for developing and 
using field monitoring methods. 

Although it is convenient to identify pathways by first considering the exposure medium 
and then considering the route, the associated exposure algorithms are route specific. Aggregate 
assessments for children must include all three exposure routes: inhalation, dermal contact, and 
ingestion. In addition, ingestion can be divided into two important subroutes, dietary and indirect 
ingestion [i.e., ingesting pesticides from contaminated objects (including food) and hands placed 
in the mouth]. 

The exposure algorithm defines the measurement approach. For each route, the algorithm 
mathematically expresses exposure as a function of pesticide concentration in the exposure 
medium, contact rate, rate of transfer from the exposure medium to the portal of entry, and 
exposure duration. The basic components of the algorithm are used to define the monitoring, 
activity pattern, and source usage data that must be collected to estimate exposure. 

Algorithms are applied separately to all of the microenvironments and activities that an 
individual experiences in a given time period. Within this document, microenvironment is 
referred to as the location where an individual spends time. For inhalation exposure, Duan 
(1982) defined a microenvironment as “a [portion] of air space with homogeneous pollutant 
concentration.” It has also been defined as a volume in space, for a specific time interval, during 
which the variance of concentration within the volume is significantly less than the variance 
between that microenvironment and surrounding microenvironments (Mage, 1985). For dermal 
exposure, microenvironment has been defined based upon the location and surface type. 
Homogeneity of the surface concentration has been considered within the algorithms. 

Activities are defined as either macroactivities or microactivities. Macroactivity is a 
series of contact events in the same microenvironment and the same activity level that are 
aggregated for the purposes of estimating dermal exposure. The macroactivity approach has 
been used extensively for estimating worker exposures to pesticides. For children, an example of 
a macroactivity would be lying on a carpeted floor for one hour watching television in the family 


15 



room. Microactivities are defined as discrete, individual, skin-to-surface or object-to-mouth 
events, such as when a child puts a toy in his/her mouth. 

Exposure models for assessments use one of two general approaches: a time-series 
approach that estimates microenvironmental exposures sequentially as individuals go through 
time, or a time-averaged approach that estimates microenvironmental exposures using average 
microenvironmental concentrations and the total time spent in each microenvironment. The 
time-series approach to modeling personal exposures provides the appropriate structure for 
accurately estimating personal exposures (Esmen and Hall, 2000; Mihlan et al., 2000). In 
addition, the time-varying dose profile of an exposed individual can be modeled only by using 
the time-series approach (McCurdy, 1997, 2000). However, a time-averaged approach is 
typically used since the input data needed to support a time-series model are usually not available 
or cannot be easily collected. Real-time monitoring techniques for measuring pesticide 
concentrations are very limited. Most environmental monitoring provides either an integrated 
24-hour concentration (as in air or duplicate diet samples) or a single time-point concentration 
(as in transferable residue samples). Thus, the algorithms presented here use a time-averaged 
approach over a 24-hour period. They could, however, be modified to provide time-series data, 
especially for activity patterns. 

Approaches for aggregating exposure estimates across routes are not presented here. 

Since absorbed dose may be different depending upon the route, it is not appropriate to sum 
exposure across routes. Exposure for each route is estimated independently. These exposures 
can then be used as inputs to exposure/dose models to estimate dose. The algorithms presented 
here are similar to those used elsewhere in the literature (U.S. EPA, 1997a; U.S. EPA 1997b). 

3.2 Inhalation Route 

Inhalation exposure may result from pesticides applied indoors or due to infiltration of 
pesticides applied adjacent to buildings. Although current use pesticides, such as the pyrethroids, 
are generally less volatile than many of the pesticides previously used indoors (e.g., chlorpyrifos), 
they may be detected in the air following application. 

Exposure Algorithm. Inhalation exposure is estimated for each of the micro¬ 
environments where a child spends time and each macroactivity that would result in a different 
inhalation rate while engaging in that activity. Exposure over the 24-hour period is then the sum 
of all of the microenvironmental/macroactivity (me/ma) exposures. This may be expressed 
mathematically as: 



= EE, 


ime/ma 



where 

E i24 = the total inhalation exposure over a 24-hour period (pg/d) 


16 


Eime/ma ~~ the inhalation exposure for a given me/ma over a 24-hour period (pg/d) 
For each me/ma, inhalation exposure over the 24-hour period (E ime/ma ) is defined as: 


E 


ime/ma 


^ame ^ I'me/ma ^ i^ma 


( 2 ) 


where 


w ame 

T , 

me/ma 

IR„a 


the air concentration measured in the micro environment (pg/m 3 ) 
the time spent in that me/ma over the 24 hour period (h/d) 
the child’s inhalation rate representing his activity level for that 
macroactivity (m 3 /h) 


Data Requirements. In order to apply the above model, the following data are required: 


• Definition of the important microenvironments/macroactivities for inhalation 
exposure. Four generalized microenvironments have been defined for very young 
children (4 years old and younger). These include indoors and outdoors at home and 
indoors and outdoors at daycare centers. If the air concentrations indoors are not 
homogenous, there may be more than one microenvironment indoors at home or indoors 
at daycare. There may also be other indoor and other outdoor microenvironments that 
are important if the child spends substantial amounts of time away from the home or 
daycare. Four macroactivities have been defined for children: sleeping/napping, active 
play, quiet play, and eating. 

• Air concentration in each microenvironment. Ideally, an integrated air concentration 
should be measured only during the time that the subject is in each microenvironment. 
Alternatively, an integrated 24-hour measurement should be adequate if it is assumed that 
air concentrations do not vary substantially over time or space within any 
microenvironment. Since the air concentration for the other indoor and other outdoor 
categories will not be measured, an approach for developing a reasonable estimate must 
be made. This estimate becomes important for inhalation exposure if the subject spends 
substantial time in these other microenvironments. 

• Amount of time the child spends in each me/ma over 24-hours. The amount of time a 
child spends in each microenvironment/macroactivity is collected with a time-activity 
diary for the period of monitoring. The diary, at a minimum, should record the child’s 
time in each microenvironment and information on the child’s activities that can be used 
to estimate inhalation rate while in that microenvironment. 

• Inhalation rate for each me/ma. The rate of inhalation will be estimated based on age 
and weight of the child and activity in each microenvironment. 

Table 3-1 summarizes the data requirements as they relate to equation (2) to estimate 

exposure by the inhalation route. 


17 


Table 3-1. Summary of Data Collection Requirements by Exposure Route 


Parameter 

Measurement 

How Collected 

Units 

Inhalation Exposure 

E ime/ma ^ame ^ T me / ma X IR-mg 

^ame 

Air concentration in me 

Measured with active sorbent 
collection 

pg/m 3 

T 

me/ma 

Time spent in each 
me/ma 

Time-activity diary, questionnaire 

h/d 

IRma 

Inhalation rate 

Estimated from size, age, and 
activity data collected with diaries 
and questionnaires using reference 
values 

m 3 /h 

Dermal Exposure - Macroactivity Approach 

b'dm&'ma ^surf ^ TC me y ma X AD^^^ 

^surf 

Surface loading (total or 
transferable) in each me 

Measured by wipe, press, or roller 
methods 

pg/cm 2 

TC ^ 

^me/ma 

Transfer coefficient 3 

Empirically determined for each 
me/ma from laboratory 
experiments or field studies 

cm 2 /h 

me/ma 

Activity duration for ma 
in a specific me 

Time-activity diary, questionnaire 

h/d 

Dermal Exposure - Microactivity Approach 

E dmi = C^xTExSAxEF 

c 

'-'surf 

Surface loading (total or 
transferable) in me 

Measured by wipe, press, or roller 
method 

pg/cm 2 

TE 

Transfer efficiency 3 

Empirically determined from 
laboratory experiments 

unitless 

SA 

Surface area contacted 

Visual observation or videotape 

cm 2 /event 

EF 

Frequency of contact 
events 

Visual observation or videotape 

events/d 

Dietary Ingestion Exposure 

E f = S C f W f 

C f 

Concentration of pesticide 
in the food item (s) 

Measurement in individual food 
items or composite duplicate diet 
samples 

Pg/kg 


18 



































Parameter 

Measurement 

How Collected 

Units 

W f 

Weight of food item 
consumed 

Measured in duplicate diet sample 

kg/d 

Indirect Ingestion Exposure - Microactivity Approach 

Eingmi = C x x TE X x SA X x EF 

E-surfx 

Surface loading (total or 
transferable) on object x 

Measure by a wipe or press 
method 

pg/cm 2 

TE X 

Transfer efficiency 3 

Empirically determined from 
laboratory experiments 

unitless 

SA X 

Surface area contacted 

Visual observation or videotape 

cm 2 /event 

EF 

Frequency of mouthing 
events 

Visual observation or videotape 

events/d 


a This parameter must be calculated using the same surface loading measurement method as used to 
measure C^ 


3.3 Dermal Route 

Two main approaches are currently used to assess dermal exposure. These assessment 
approaches provide different ways of integrating exposure over time and space. In the 
macroactivity approach, exposure is estimated individually for each of the microenvironments 
where a child spends time and each macroactivity that the child conducts within that 
microenvironment. To do this, exposure is estimated using empirically derived transfer 
coefficients to aggregate the mass transfer associated with a series of contacts with a 
contaminated medium. 

In the microactivity approach, exposure is explicitly modeled as a series of discrete 
transfers resulting from each contact with a contaminated medium. To estimate dermal exposure 
with the microactivity approach, exposure must be estimated for all contacts made by child 
during a 24-hour period. To use the microactivity approach, a substantial amount of detail is 
needed to characterize children’s dermal contact with chemical residues in all of their 
microenvironment/macroactivity combinations and to quantify subsequent dermal absorption. 
These data include: definitions of the microenvironments/macroactivities that are important for 
dermal exposure; surface loading measurements (total or transferable surface residue) for each 
microenvironment/macroactivity combination; amount of time a child spends in each 
microenvironment/macroactivity during a 24-h period; the transfer coefficient for each 
microenvironment/macroactivity; surface area of exposed skin; contact frequency of exposed 
skin in a given microenvironment; and transfer efficiency for each microactivity. Collection of 


19 


















this level of detailed data is extremely resource intensive and not practical in most field 
measurement studies. The microactivity approach can be applied in small research studies, but 
has limited utility for exposure measurement studies. Therefore, although the algorithm is 
described below, methods for collection of the required data are not described in this protocol. 

3.3.1 Macroactivity Approach 

Exposure Algorithm. To estimate exposure using the macroactivity approach, 
microenvironments are defined by location and surface type. Macroactivities (i.e., active play, 
quiet play, sleeping/napping, and eating) are defined based on the expected magnitude and 
variability of the pesticide transfer coefficient. For any given microenvironment/macroactivity 
combination transfer coefficients are developed using carefully controlled laboratory or field 
studies. Exposure in field studies can then be estimated individually for each of the 
microenvironments where a child spends time and each macroactivity that the child conducts 
within that microenvironment using transfer coefficients and the surface loading in the 
microenvironment. The surface loading may be either the total residue concentration present on 
a surface or the amount of pesticide residue on the surface that is available for transfer to the skin 
(referred to as the transferable residue). Different methods are used to make the measurements of 
these two categories of residues, as discussed in Section 6.0. 


Exposure over a 24-hour period is the sum of all the microenvironment/macroactivity 
exposures, expressed as: 


E 


derm24 


- EE 


dme/ma 


(3) 


where 

E derm24 = dermal exposure over a 24-h period for all microenvironments and 
macroactivities (pg/d) 

Edme/ma = dermal exposure for a given microenvironment/macroactivity combination 
(Hg/d) 


For each microenvironment/macroactivity combination, dermal exposure is defined as : 

Edme/ma (Csurf)(EC me/ma )(AD me/ma ) (4) 


where 


'dme/ma 


''-'surf 

TC 


me/ma 


AD 


me/ma 


dermal exposure for a given microenvironment/macroactivity combination 
over a 24-h period (pg/d) 

surface loading (total or transferable) measured in the microenvironment 
(|ig/cm 2 ) 

transfer coefficient for the microenvironment/macroactivity (cm 2 /h) 
activity duration that represents the time spent in each 


20 


microenvironment/macroactivity combination with a specific clothing 
pattern for the child that would affect the surface area available for transfer 
over a 24-h period (h/d) 

The transfer coefficient, TC me/ma , provides a measure of dermal exposure resulting from 
contact with a contaminated microenvironmental surface while engaged in a specific 
macroactivity. The transfer coefficient takes into account the fraction of the transferable surface 
residue that is transferred from a surface to skin, the character of the microenvironmental surface 
that is contacted, and the area of the microenvironmental surface that is contacted during a time 
increment for a given activity. Transfer coefficients are empirically derived in laboratory tests or 
controlled field experiments. TC der can be defined as follows: 


TC 


me/ma 


= (E 


dme/ma) 


/ (C sur f)(AD me/ma ) 



Data Requirements. Table 3-1 shows the data requirements as they relate to equation 
(4) which is used to estimate dermal exposure by the macroactivity approach. The following data 
will be required for each microenvironment/macroactivity combination to estimate dermal 
exposure: 


Definition of the microenvironments/macroactivities that are considered important 
for dermal exposure. These microenvironments/macroactivities account for: 

• Various microenvironments with different residue concentrations, 

• Various types of surfaces that affect the transfer rate, 

• Child activities that affect the transfer coefficient. Macroactivities have been 
selected that should have fairly uniform transfer coefficients within a 
microenvironment. 

Surface loading. For each microenvironment/surface combination, measurements will 
be made on those surfaces for which the child is expected to have substantial contact. 
Measurements should provide a representative loading for the entire area of contact. The 
measurement may be of total residue or the transferable residue. 

Amount of time the child spends in each microenvironment/macroactivity during a 
24-h period. These data can be collected using a time-activity diary or questionnaire. 
Transfer coefficient for each microenvironment/macroactivity. These are data that 
are currently not available. NERL is in the process of developing specific children’s age 
related transfer coefficients in the laboratory and in controlled field experiments. 
Clothing pattern for the child that would affect the surface area available for 
transfer. The amount of clothing and exposed skin needs to be determined. 


3.3.2 Microactivity Approach 

Exposure Algorithm. To assess dermal exposure using the microactivity approach, 
exposure is estimated individually for all of the microactivities in a given microenvironment in 


21 


which dermal contact occurs. Exposure over a 24-h period is then the sum of all of the 
individual exposures: 


where 

F 

J -'derm24 

i 



Ederm24 = ZZ^dmi (6) 

> j 

dermal exposure over a 24-h period for all microactivities (pg/d) 
sum of all microenvironments 

sum of all microactivities in a given microenvironment 
dermal exposure for each microactivity over a 24-h period (pg/d) 


For each microenvironment/microactivity, dermal exposure over a 24-h period can be defined as: 


E dmi = (C sur f)(TE)(SA)(EF) 


(7) 


where 

E dmi = dermal exposure for each microactivity over a 24-h period (pg/d) 

C sur f = surface loading (total or transferable) measured in the microenvironment 

(|xg/cm 2 ) 

TE = transfer efficiency, fraction transferred from surface to skin (unitless) 

SA = surface area contacted (cm 2 /event) 

EF = frequency of contact events during a 24-h period (events/d) 

Transfer efficiency is defined as the fraction of mass transferred from a contaminated surface to 
skin per unit contact and can be represented as follows: 


TE = (L mi ) / (C surf ) 


( 8 ) 


where 

L mi = loading (pg/cm 2 ) on the transfer medium (i.e., skin) 

Data Requirements. To use the microactivity approach, a greater level of detail is 
needed to characterize children’s dermal contact with chemical residues in their environments. 
Given the greater level of detail that is required, the microactivity approach is not used for 
directly estimating exposure in field studies. Rather, it is applied to indirect modeling 
assessments. Data are usually only collected on exposure factors, most particularly in the form of 
videotaping children’s activities. Data required to estimate dermal exposure include: 

• Definition of the microenvironments that are considered important for dermal 
exposure. The microenvironments should account for: 

• Various microenvironments with different residue concentrations, 

• Various surfaces that affect the transfer rate, and 


22 


• Clothing worn by the child. 

• Contact frequency of exposed skin in a given microenvironment. This is determined 
using a videography method or direct visual observations. 

• Surface area of skin exposed during contact. Data are collected on a child specific 
basis. 

• Parameters describing the nature of the contact for each microactivity. Information 
should be collected on a child specific basis on those parameters that influence transfer 
efficiency from the surface to the skin. Currently, this information is not available; 
however, research at NERL is underway to identify these parameters. Potentially 
important contact parameters include duration, pressure, motion, and skin surface (sticky, 
wet, dry). 

• Surface loading at the point of contact. When surface loadings are not homogenous, 
data should be collected for every point on the surface where contact is made. 
Unfortunately, measurement data in this detail cannot be collected in a field study. Thus 
pesticide distributions within each microenviomment must be modeled using data 
generated during laboratory experiments or carefully controlled field experiments. 
Sufficient field measurement data should be available to verify the modeled distributions. 

• Transfer efficiency for each microenvironment and microactivity. These are data that 
are currently not available and need to be generated experimentally in controlled 
laboratory experiments. 

Table 3-1 shows the data requirements as they relate to equation (7). 

3.4 Ingestion Route 

Characterizing ingestion of pesticides by children may involve several pathways: 

• Direct ingestion of foods brought into the home or other eating places containing 
pesticide residues primarily from agricultural applications, but also from contamination 
during storage and preparation in the residential or other environments (i.e., dietary 
ingestion), 

• Ingestion of foods that have been contaminated as the result of contact with contaminated 
hands and surfaces during preparation and consumption, 

• Pesticide residues ingested while mouthing contaminated hands and objects, and 

• Ingestion of contaminated soils or contaminated house dust found in the residential or 
other environments. 

A conceptual model of the potential pathways for ingestion exposure is presented in 
Figure 3-1. Ingestion pathways 2 through 4 above are referred to here as indirect ingestion and 
may be the result of hand-to-mouth, object-to-mouth, or hand-to-object-to-mouth activity where 
the objects may be items such foods contaminated while being consumed or toys contaminated in 
the child’s environment as a result of routine activities. 


23 


Figure 3-1. Conceptual model of pesticide exposure by the ingestion route. 



Transfer by mouthing 


24 





















Infants and young children may be particularly vulnerable to exposure by the ingestion 
route for several reasons. The specific foods comprising the diets children eat may result in 
higher dietary ingestion of contaminants and children eat more relative to their body weights than 
adults. Indirect ingestion of contaminants may also occur when children handle and eat foods 
that have come in contact with the floor or other contaminated surfaces. In many cases, indirect 
ingestion may occur after repeated contacts of the same object (food or any other object that 
enters the mouth) with multiple contaminated media, and from multiple contacts with the mouth. 
For example, a food item may contact several surfaces, including eating surfaces, hands, and 
utensils, before it is partially or completely ingested. Finally, children’s mouthing activities will 
result in indirect ingestion of environmental contaminants if the hands or non-dietary objects 
entering the mouth are contaminated. 

3.4.1 Dietary Ingestion 

To determine the ingestion of pesticides through the dietary pathway, duplicates of all 
foods consumed (i.e., duplicate diets) during the monitoring period are collected and analyzed. 

In duplicate diet studies for children, a caregiver generally provides second portions (e.g., a 
duplicate plate) of the foods given to the child for consumption. The portions are identical to 
what has been served to the child with respect to preparation, type of food, and amount of food. 
Following the eating activity by the child, portions are adjusted to account for foods not 
consumed (e.g., a duplicate diet). The distinction between a duplicate plate (consisting of all 
foods served) and a duplicate diet (consisting of all foods eaten) is typically more significant for 
children than adults because significant quantities of food may be left uneaten. During the brief 
monitoring period for the child, duplicate diet methodology should provide the most accurate 
measure of dietary exposure because it accounts for all foods consumed, even those from non¬ 
commercial sources (Thomas et al., 1997). It accounts for gains or losses of the contaminant that 
may occur during transport, storage, and preparation, and most importantly, when combined with 
methodology to assess indirect ingestion during consumption, measures the actual and total 
contaminant intake for the child during the exposure monitoring period. 

Duplicate diets are collected over some specific period of time, with one day being the 
time increment most often used (i.e., for acute assessment). For longer periods (i.e., short-term, 
intermediate term or chronic assessments), multiple consecutive or non-consecutive days may be 
used to better describe the child’s contaminant intake, since there is the potential for a large daily 
intake variability. In some cases, particularly for risk assessment, it may be necessary to collect 
duplicate diet samples at different times of the year to assess seasonal intake variability. 

Exposure Algorithm. Assessing the dietary ingestion of a contaminant is estimated by 
the sum of the concentration of the contaminants multiplied by the amount consumed of all foods 


25 




eaten during the monitoring period. 

Ef = ECfW f 


( 9 ) 


where 

E f = the total dietary ingestion during the 24-hr period (pg/d) 

C f = concentration of pesticide in the food item (pg/kg) 

W f = weight of food item consumed (kg/d) 

Data Requirements. To assess total contaminant intake, duplicate portions of all foods 
and beverages consumed by the child must be collected and analyzed. In selected cases, a study 
may focus on the contaminant intake from a single dietary source (e.g., fish or vegetables), and 
the duplicate diet methodology can be applied to the specific food or group of foods. 

3.4.2 Indirect Ingestion 

To date, indirect ingestion has been estimated using two approaches. One approach is 
similar to the microactivity approach described in Section 3.3.2 for assessing dermal exposure by 
which each contact with a contaminated medium is described (U.S. EPA 1997b, Melnyk et al., 
2000, Akland et al., 2000). A second approach is to measure the concentration of pesticide or 
contaminant in soil or house dust and then assume a mass of soil/dust that is consumed by the 
child (U.S. EPA 1997b) in association with activities such as mouthing objects or eating foods. 

A third approach is proposed here that uses some additional assumptions to lump details 
associated with some of the exposure factors and activity patterns leading to indirect ingestion. 
This macroactivity-type approach allows for a simplified assessment of indirect ingestion 
exposure to an individual based on measurement data collected in the field and factors that 
characterize the activities that lead to indirect ingestion of contaminants. 


Exposure Algorithm for Microactivity Approach. To assess indirect ingestion 
exposure using the microactivity approach, exposure is estimated individually for all of the 
microactivities (e.g., hand-to-mouth, object-to-mouth, food-to-mouth, hand-to-food-to-mouth 
contacts) in which indirect ingestion occurs. Exposure during the 24-h period is then the sum of 


( 10 ) 


all of the individual exposures: 


k'ing/mi24 E^ing/mi 

where 


F = 

■ L 'ing/mi24 

indirect ingestion exposure 
(pg/d) 

F . = 

ing/mi 

indirect ingestion exposure 
(Pg/d) 


26 


For each microactivity, indirect ingestion exposure during the 24-h period can be defined as: 


Eing/mi = (C sur f X )(TE x )(SA xm )(EF) (11) 


where 


E: 


ing/mi 


X 

^-'surfx 

TE X 

SA xm 

EF 


indirect ingestion exposure for each microactivity over a 24-h period 

(Fg/d) 

hand, object, food item or anything else that enters the mouth 
surface loading (total or transferable) on x (pg/cm 2 ) 
transfer efficiency of contaminant from x to mouth (unitless) 
area of x contacted by mouth (cm 2 /event) 

frequency of indirect ingestion events over a 24-h period (event/d) 


For food or any other item that is ultimately consumed, TE X is equal to unity. When transfer 
from x to the mouth is for items other than food, TE X is a function of: 


Characteristics of x (hard, plush, porous, moisture, oil content, age, loading) and 
Contact mechanics (sucking, licking, duration, repetition) 


In addition, the loading of pesticide on an object (e.g., toy or food) contaminated as a result of 
contact with a contaminated residential surface (e.g., hand or floor) can be defined as: 


C surfx = (C y )(TE y )[(SA yx ) / (SA xy )] (12) 


surface loading (total or transferable) on x (pg/cm 2 ) 
hand, object, food item or anything else that enters the mouth 
surface loading (total or transferable) on surface y (pg/cm 2 ) 
contaminated residential surface 
transfer efficiency of contaminant from y to x (unitless) 
area of the object (x) contaminated as a result of contact with 
contaminated surface (y) [cm 2 ] 

area of the surface (y) contacted by the object (x) [cm 2 ] 

Note that the surface to object transfer efficiency (TE y ) is a function of: 

• Form of the pesticide (residue, particle bound, formulation, age, physicochemical 
properties), 

• Characteristics of surfaces (hard, plush, porous, loading, previous transfer), 

• Characteristics of x (moisture, oil or fat content, age, loading, previous transfer), 

• Contact mechanics (pressure, duration, smudge, repetition), and 

• Environmental conditions (temperature, relative humidity, air exchange, redeposition 


where 



y 

TE y = 
SA xy = 


SAy, = 


27 


rate). 


Data Requirements for Microactivity Approach. To use the microactivity approach, a 
significant level of detail is needed to characterize the potential for children’s indirect ingestion 
exposure to chemical residues and to quantify intake. Information and data required to estimate 
indirect exposures include the following. 

Common data needs for all events that lead to indirect ingestion exposure: 

• Information on microenvironments/macroactivities that lead to indirect ingestion, 

• Surface loadings in the important microenvironments, 

• Residue loadings on hands, if the child’s hands are in contact with objects mouthed or 
ingested, and 

• Information on an individual child’s hand washing practices. 

Data needs for indirect ingestion exposure due to hand-to-mouth activities: 

• Fraction of residue transferred from the hands to mouth during a mouthing event, 

• Number of mouthing events in a 24-h period, and 

• Surface area of hand contacted by the mouth. 

Data needs for indirect ingestion exposure due to surface (including hand)- or object-to-mouth 
activities’. 

• Information on what surfaces, body parts, toys, etc., are mouthed, 

• Surface loadings for any objects or surfaces (including hands) mouthed by children, 

• Transfer efficiency from the surface (including hands) to mouth during a mouthing event, 

• Number of mouthing events during a 24-h period, and 

• Surface area of object mouthed. 

Data needs for indirect ingestion exposure due to consumption of handledfood: 

• Information on locations where an individual child consumes foods, 

• Information on handled and consumed foods for an individual child, 

• Area of surfaces and hands contacted by food, 

• Transfer efficiency from surface or hand to food, 

• Number and duration of food-to-hand and food-to-surface contact events, and 

• Information on amount of specific foods that are consumed. 

Macroactivity Approach. Because it would be too burdensome and costly to collect all 
the data required to apply the microactivity approach for the time-sequence of events that occurs 
on an individual basis, a macroactivity approach is proposed here to provide a simplified 


28 




assessment of indirect ingestion exposure to an individual based on measurement data collected 
in the field. In this approach, objects (including hands and food) that are commonly handled, 
mouthed, and/or ingested are identified in the field. The residue loadings on these objects are 
measured directly or estimated from surface loading measurements combined with transfer 
efficiencies measured in the laboratory. General information relating to the frequency and nature 
of these mouthing and ingestion activities is also collected. Data on the fraction of residues that 
may be removed from an object during mouthing that has been collected in the laboratory is then 
required to complete the assessment. In this approach, only equations 10 and 11 are used. 
Information on each of the individual contacts and transfer leading up to a surface loading on an 
important item is lumped into the one loading measurement taken from that item. In addition, 
the items identified as most often mouthed and/or eaten are assumed to represent the most 
significant sources of indirect ingestion exposure. Note that a macroactivity approach analogous 
to the one used for dermal exposure is not recommended here for indirect exposure. Currently, a 
method for developing empirically derived transfer coefficients that lump mouthing contact, 
surface area, and transfer for a series of mouthing events does not exist. No measure of indirect 
ingestion exposure analogous to a dermal dosimeter exists. It is possible that in the future, 
controlled studies could be conducted using a nontoxic tracer that could be tracked in biological 
samples such as urine. Such a tracer would need to be applied as a surrogate for the 
environmental contaminants of interest in a setting where children could interact with the items 
of interest and exposures could be limited to indirect ingestion pathways. For now, we propose 
an approach which attempts to directly link surface loadings and indirect ingestion activities to 
provide a very basic screening assessment of indirect ingestion exposure. 

Data Requirements for Macroactivity Approach. To use this macroactivity approach 
to assess indirect ingestion exposure for an individual in a measurement study, information on 
residue concentrations and factors characterizing general contact with items that are mouthed or 
consumed is combined with transfer efficiencies that have been measured in the laboratory. 
Research is continuing on the parameters that characterize the most common eating and 
mouthing activities. The type of data that must be collected in the field include the following. 

Data needs for indirect ingestion exposure due to hand-to-mouth activities’. 

• Residue loadings on the hands, 

• General information on the frequency and nature (e.g., portion of hand that is mouthed) of 
hand-to-mouth activity, and 

• Information on an individual child’s hand washing practices. 

Data needs for indirect ingestion exposure due to surface- or object-to-mouth activities, other 
than hands: 

• Information on most commonly mouthed objects for an individual child, 

• Surface residue loading measured from these objects, and 


29 


• General information on the frequency and nature (e.g., portion of object that is mouthed) 
of mouthing. 

Data needs for indirect ingestion exposure due to consumption of handledfood: 

• Information on most commonly handled and consumed foods for an individual child, 

• Information on contacts of foods with intermediate surfaces, including hands, 

• Samples of these foods collected after handling, and 

• General information on amount of these foods that are consumed. 


30 


4.0 EXPOSURE SCENARIO 


While many of the methods and approaches presented in this protocol should be generally 
applicable or easily modified to address many children’s exposure scenarios, this protocol 
focuses on exposure of infants and young children to pesticides. The exposure scenarios used in 
the development of this protocol are summarized in Table 4-1 and described below. 


Table 4-1. Scenario for Protocol Development 


Parameter 

Description 

Pesticide Source 

Any residential or daycare pesticide application 

Exposure Population 

Children 4 years old or younger 

Time Frame for Exposure 

Short-term, 1 to 7 days following application 

Microenvironments 

Indoors at home, outdoors at home, indoors at daycare 
centers, and outdoors at daycare centers 

Activities 

Active play, quiet play, sleeping, and eating 


Sources. This protocol focuses on sources of pesticides in the residential and daycare 
center environments. Indoor sources include: regularly scheduled professional crack and crevice 
applications; general residential use of off-the-shelf formulations; and outdoor sources of turf and 
garden pesticides. Following outdoor applications, exposure indoors may occur due to 
infiltration of outdoor air into the residence or daycare or track-in of residues or particle-bound 
pesticides. 

For dietary exposures to occur, foods must contain pesticide residues, then the food must 
be consumed. Many different sources can contribute to dietary residues and subsequent 
exposure: foods containing pesticide residues are purchased from a commercial source and eaten; 
foods containing residues are obtained from a noncommercial source (i.e., home gardens) and 
eaten; and, foods from either commercial or noncommercial sources are obtained then 
subsequently contaminated during transport, storage, or preparation. Lastly, foods from all 
sources can be subsequently contaminated during consumption by a child (i.e., indirect ingestion 
exposure). 

Exposed population. The protocol describes the approaches for estimating the 
exposures of children 4 years old or younger. Very young children may be particularly 


31 












susceptible to pesticide exposures as the result of the microenvironments in which they spend 
time (e.g., kitchen floor), and the activities in which they are involved (e.g., mouthing of hands 
and toys and handling foods). It is important to understand that physiological characteristics and 
behavioral patterns will result not only in different exposures for children and adults, but also for 
children of different developmental stages. Thus, exposure assessments are required for children 
in each age group, with age group being defined by developmental stage. Developing a 
classification scheme for children by age group has been the subject of significant debate. The 
Risk Assessment Forum (RAF) held a workshop on this topic in July of 2000 (U.S. EPA, 2000b). 
Some examples associated with relevant age-related developments for several exposure pathways 
are presented in Table 4-2. The age bins recommended by the RAF workshop for classifying 
children based on behavior are presented in Table 4-3. 


Table 4-2. Relevant Age-Related Developments (From U.S. EPA, 2000b) 


Exposure Pathway 

Examples of Relevant Age-Related Developments 

Breast Milk/Nursing 

Nursing takes place roughly from 0 to 18 months of age, though this varies by 
culture. 

Bottle Feeding 

Bottle feeding takes place roughly from 0 to 12 or 24 months. 

Food 

Head control (2 months), sitting (6 months), finger feeding (8 to 9 months), 
use of utensils (10 to 12 months), and the final shift to adult patterns of eating. 
Solid food, served in a bottle as a slurry, is often consumed as early as 1 
month of age, but 4 to 6 months is the typical age range for beginning solid 
foods by themselves. 

Water 

Use of cups (6 to 9 months). 

Mouth-Hand Contact 

Prevalence of hand-to-mouth behaviors, such as thumb-sucking. Gross motor 
skills determine access to areas where the hand can become contaminated. 
Succession of gross motor milestones: rolling (4 months), creeping 
(6 months), crawling (8 months), walking (12 months), and climbing 
(18 months). 

Mouth-Object 

Contact 

The ability to interact with objects is a major factor. The ability to grasp an 
object to one’s mouth begins roughly at 3 to 5 months. A pincer grasp and 
moderate strength are achieved by 9 months. Children become aware that 
objects exist even when covered around 6 months but generally do not 
understand the meaning of the word “no” until 12 months. 


32 














Table 4-3. Behavioral Age Bins (From U.S. EPA, 2000b). 


Age Bin 

Characteristics Relevant to Oral and Dermal 
Exposure 

Characteristics Relevant to 
Inhalation Exposure 

0 to 2 months 

Breast and bottle feeding. Hand-to-mouth 
activities. Rapid growth makes children 
particularly vulnerable to chemicals. 

Children spend a great deal of 
their time asleep. 

3 to 5 months. 

Solid food is introduced. Contact with surfaces 
increases. Object-to-mouth activities increase. 

Children may breathe close to 
floor level when placed in play 
pens or infant seats on the floor. 

6 to 11 months 

Food consumption expands. Children’s floor 
mobility increases. Children are increasingly 
likely to mouth non-food items. 

Development of personal dust 
clouds. 

12 to 23 
months 

Children consume a full range of foods. They 
participate in increased play activities, are 
extremely curious, and exercise poor judgment. 
Breast and bottle feeding cease. 

Children walk upright, run, and 
climb. They occupy a wider 
variety of breathing zones and 
engage in more vigorous 
activities. 

2 to 5 years 

Children begin wearing adult-style clothing. 
Hand-to-mouth activities begin to approximate 
adult patterns. 

Occupancy of outdoor spaces 
increases. 

6 to 10 years 

There is decreased oral contact with hands and 
non-food items, as well as decreased dermal 
contact with surfaces. 

Children spend time in school 
environments and begin playing 
sports. 

11 to 15 years 

Smoking may begin. There is an increased rate 
of food consumption. 

Increased independence. Work 
outside of home begins. 

16 to 20 years 

High rate of food consumption continues. 

Independent driving begins. 
Expanded work opportunities. 


Time frame of exposure. This protocol focuses on high-level, short-term (one to seven 
days post-application) exposures resulting from recent pesticide applications. This time frame 
may result in relatively high exposures. Because the explicit focus of this research is exposure 
and not health risk, the relative health implications from a series of higher short-term exposures 
versus lower chronic exposures were not considered although this is an important question 
requiring a significant research effort. It is also assumed that for this time frame for indoor 
applications, pesticides are primarily present in the form of residues, rather than being particle- 
bound. 


33 















Microenvironments of exposure. The protocol addresses data collection in residential 
dwellings and daycare centers, which are considered the most important microenvironments for 
the exposure of infants and very young children. Both the indoor and outdoor 
microenvironments are considered. 

Activities that result in exposure. Exposure associated with children’s normal daily 
activities are considered here. These include sleeping, quiet play, active play, and eating. The 
activities most likely to result in significant exposures are likely to vary with the developmental 
stage of the child. Activities specifically of interest for the ingestion pathways include all eating 
and mouthing activities. 

Assumptions. The most important assumptions made in applying this protocol for 
assessing exposure for this scenario are as follows: 

• The most significant concentrations of pesticide in this exposure time frame are present 
as residues, 

• The distribution of the pesticide residues on foods, objects, surfaces, and in the air in the 
residential environment is not homogeneous, 

• Measurement of residues on hands, objects, and foods collected at specific time points 
can be used to estimate ingestion exposures over the time frame of interest, and 

• In the time frame of concern for this scenario (short-term following an application), 
exposure resulting from ingestion of soil and house dust is less important than indirect 
ingestion of residues. 

For dietary exposure, transport, storage, preparation, and consumption may have an affect 
on the pesticide levels in the foods. All but the consumption aspects of these activities are taken 
into consideration when duplicate diet samples are collected. The most important assumptions 
made for assessing dietary exposure by the duplicate diet methods are as follows: 

• Sample collected represents the foods consumed by the child, 

• The portion sizes are adjusted for actual amounts of foods eaten, 

• The variability in pesticide levels in the foods collected and those eaten is very small, and 

• Exposures are only representative of those incurred during the monitoring period. 


34 


5.0 


APPROACH FOR ESTIMATING INHALATION EXPOSURE 


5.1 Introduction 

Inhalation is a potentially important route of exposure to pesticides for children in 
residences, daycares, schools, and other microenvironments. Inhalation exposure depends on 
many factors including the physical characteristics of the pesticides (e.g., vapor pressure), 
formulation, application method (e.g., crack and crevice application versus room fogger), 
location of application (e.g., indoors, outdoors, basement, living areas), and factors related to the 
macroenvironment (e.g., air exchange rate of the building, mixing between rooms, indoor 
temperature). Inhalation exposure may be more significant for very young children than for older 
children or adults. Infants and young children have a higher resting metabolic rate and rate of 
oxygen consumption per unit body weight than adults. They may also spend more time indoors 
and in closer proximity to pesticide sources (e.g., while playing or sitting on the floor). Young 
children who spend substantial amounts of time in residences may also have potentially higher 
inhalation exposure than children in daycares or schools due to lower air exchange rates in homes 
than in commercial buildings. However, the latter types of buildings may have higher pesticide 
usage than residences. 

Inhalation exposure has been estimated for a wide range of volatile and semi-volatile 
organic compounds, including pesticides. There have been a number of studies involving 
measurements of pesticides in air (e.g., Lewis, et al., 1994; Whitmore et al., 1994; Gordon et al., 

1999; Quackenboss et al., 2000). Much of the prior data on indoor air concentrations are for 
concentrations of organophosphorous, organochlorine, and other pesticides that are not currently 
used indoors. There are few data available on pesticides currently used indoors, such as the 
pyrethroids. Of all the potential routes of exposure to pesticides, inhalation has been studied the 
most. The protocols and methods for measurements of pesticides in air are the most well- 
developed of the aggregate exposure measurement methods. 

5.2 Summary of Data Requirements 

As described in Section 3.2, inhalation exposure is estimated for each of the 
microenvironments where a child spends time and for each macroactivity that would result in a 
different inhalation rate while engaged in that activity. Exposure over the 24-hour period is then 
the sum of all of the microenvironmental/macroactivity (me/ma) exposures. 

The data required to estimate inhalation exposure are summarized in Table 5-1. 

5.3 General Considerations 

To estimate inhalation exposure for young children, it is necessary to use stationary 
samplers in selected microenvironments to collect air samples for pesticide analyses. Although 


35 


Table 5-1. Data Requirements for Estimating Inhalation Exposure Route 


Parameter 

Measurement 

How Collected 

Units 

Inhalation Exposure 

^ime/ma ^-'ame ^ ^me/ma ^ ^^ma 

c 

^ame 

Air concentration in me 

Active sorbent collection 

pg/m 3 

T 

me/m a 

Time spent in each 
me/ma 

Time-activity diary, 
questionnaire 

h/d 

IR™ 

Inhalation rate 

Estimated from size, age, and 
activity data collected with 
diaries and questionnaires and 
using reference values 

mVh 


a preferred method for measuring an individual’s exposure to air contaminants is to have the 
study participant wear a personal exposure monitor (PEM), this method is not suitable for young 
children less than 4 years old. Because it is not possible to measure the air concentrations in all 
microenvironments that a child may occupy, it is important to identify which microenvironments 
represent the highest potential exposures based on the amount of time spent in each micro¬ 
environment. For children age 0 through 4 years, the important microenvironments include the 
residence and daycares. For infants, measurement of air concentrations in the home, preferably 
in the room where the infant spends the most time during the day, will be representative. 

Because of the small amount of time spent outdoors and the low outdoor concentrations relative 
to indoor concentrations after pesticide applications, it may not be necessary to measure outdoor 
air concentrations to estimate an infant’s inhalation exposure. As children age and spend more 
time outdoors, it becomes important to measure outdoor air concentrations, although the levels 
may be very low for most pesticides. 

Microenvironment/macroactivity data need to be collected to identify all of the important 
microenvironments that a child may occupy. If there are important microenvironments other 
than the residence and daycare, it is necessary to estimate air concentrations in those micro¬ 
environments. To make these estimates, it is generally necessary to assume that there have been 
no recent applications of the pesticides of concern in that microenvironment and a reasonable 
concentration must be used for the exposure estimate. This reasonable concentration would be 
the background concentrations measured outdoors or in indoor microenvironments without 
recent applications of the target pesticide. 

Measurements of indoor air concentrations of pesticides require active pumping systems 
to collect air samples on sorbent media. Placement of the sampling equipment indoors presents a 


36 
















variety of sampling challenges because of presence of the occupants, including small children, 
and the restricted space in indoor environments. Because air monitoring is often intrusive, it is 
particularly important that field personnel be sensitive to the burden placed on study participants. 
Pump noise is a critical concern when sampling indoors, particularly in sleeping areas. Low- 
noise pumps must be used indoors. Noise may be minimized by placing pumps in a small ice 
chests or metal boxes containing sufficient acoustic insulation to baffle the sound of pump 
motors. Pumps may be located in closets or behind furnishings to further minimize noise and 
remove the apparatus from traffic zones. 

Because the sampling equipment is left unattended at the sampling site, field teams must 
consider both the safety of the children in the location where sampling is performed and the 
potential for tampering with instrumentation or theft (outdoors). Extreme care must be taken so 
that the pumps, sampling trains, and sorbent tubes pose no safety concerns. Samplers can not be 
accessible to children or placed on stands that can be tipped over. There should be no small parts 
that could be removed by children that could cause potential choking hazards. If glass sampling 
cartridges are used, they must be protected with unbreakable shields that prevent breakage or that 
will contain all media if breakage occurs. Pumps and sampling cartridges should be place out of 
the reach of small children. Appropriate security measures include placing pumps in locked 
boxes, tamper proof shielding over the pump controls, and the placement of sampling apparatus 
out of the reach of small children and pets. 

Power sources may be unstable in some locations and may produce disruptions during 
monitoring activities. When possible, battery back-up or an un-interruptible power source should 
be used to decrease the impact of these occurrences on sample collection. 

Selection of sampling locations within a room is important to obtain representative air 
concentrations. As discussed in the following section, samplers should be placed at an 
appropriate height and location in the room. They should not be placed near windows, air supply 
diffusers or returns, or other locations where the air flow may affect air concentrations. 

5.4 Monitoring and Sampling Methods 

Measurements of pesticides in air for estimates of young children’s inhalation exposure 
require collection of air samples with active sampling systems consisting of sorbent media and 
vacuum pumps. Concentrations of pesticides in air are obtained by collection of integrated air 
samples on the sorbent media, extraction of the sampling media, and analysis by an appropriate 
method, generally gas chromatography (GC) or high performance liquid chromatography 
(HPLC). 

Pesticides are semi-volatile compounds with saturation vapor pressures of less than 10' 2 
kPa. Many of the synthetic pyrethroids (e.g., cyfluthrin, cypermethrin, esfenvalerate) that are 
currently used for indoor applications, have saturation vapor pressures of less than 1 O' 8 kPa As a 


37 


result, the air concentrations of these compounds are generally low and decrease rapidly 
following an application (Lewis et. al., 2001). Sampling and analysis methods for the current 
generation of pesticides applied indoors must address the low volatility and potentially low 
concentrations. The methods must have sufficiently low detection limits and good performance 
characteristics at low levels. As an example, the median concentrations of chlorpyrifos and 
diazinon, which are relatively volatile compounds compared to pyrethroids and other current use 
pesticides, were 8.0 and 4.6 ng/m 3, respectively, in the Arizona NHEXAS samples (Gordon et al., 
1999). 


The collection of airborne pesticide residues on sorbent media is generally performed 
using commercially available small, portable, low volume pumps that can be operated over a 
range of flow rates of 0.1 to 4 L/min. The pumps, which can be operated on batteries or with AC 
power, must be sufficiently quiet for use in occupied environments and suitable for collection of 
integrated samples over a 24 hour period. It should be noted that these monitoring pumps as 
purchased are typically powered by rechargeable NiCad battery packs and are generally designed 
for 8 to 16 hour occupational exposure monitoring. These pumps may not have sufficient battery 
life for a 24 hour monitoring, but can usually be modified by a qualified electronics technician or 
by the manufacturer to operate using disposable alkaline batteries to provide adequate run times. 
Such modifications will generally void warranties and void the intrinsic safety of the pump for 
use in hazardous locations. Operation of the pumps on AC power circumvents the need to 
modify the pumps but lack of easily accessible power outlets may add significant set-up time, 
create safety hazards by requiring the use of extension cords, or force the collection of samples in 
less desirable locations due to the difficulties of having to supply AC power. Pump failures may 
also be caused by unstable or interrupted AC power. If rechargeable batteries are used, care must 
be taken to insure that the batteries are discharged and charged properly to minimize failure due 
to charge memory effects. Likewise, if alkaline batteries are used, voltages of the batteries 
(especially partially used batteries) should be determined prior to beginning sample collection to 
insure that the batteries will provide sufficient power to operate the pumps for the desired time 
period. 


Flow rates of sampling pumps are set to obtain a specified volume based on the duration 
of the monitoring period, retention efficiency of the target pesticides on the sorbent, and the 
sensitivity of the analytical method. High volume pumps are not appropriate for sampling 
indoors because of considerations of noise and the impact that collection of high air volumes 
indoors may have on air exchange rates and air movement in the rooms. High volume pumps 
may be used outdoors. 

A variety of sampling media are available for collection of pesticides in air. Available 
sorbents include polyurethane foam (PUF), Amberlite® XAD-2, Amberlite® XAD-4, 
Chromosorb® 102, Tenax® GC or TA, and Porapak®-R. These absorbents have similar 
efficiencies for collection of most pesticides (Lewis, 2000). PUF has been used as the sorbent 
media in a number of field measurement studies (e.g., Whitmore et al., 1994; Gordon et al., 


38 


1999) and its use is described in an ASTM standard practice (ASTM, 2000a). XAD resin has 
been used extensively for collection of semi-volatile organic compounds (U.S. EPA, 1999b) and 
can be used as an alternative to PUF. 

Sorbent media may be used individually or in multi-bed combinations. The sample 
media may be constructed in series to collect both gas phase residues as well as levels of airborne 
particles. The sampler may consist of a combination of particle sizing devices (to collect only 
inhalable or respirable particles below 10 or 2.5 pm diameter), membrane filters to collect 
particles, sorbent resins, and/or polyurethane foam. Selection of the sampling media should be 
based on the physio-chemical characteristics of the compound(s) of interest, sampling efficiency, 
retention efficiency, performance characteristics based on available literature or laboratory 
validation studies for all analytes of interest, cost, and ease of use. 

The selection of the multi-residue sampling and analysis methods should consider the 
following factors: 

• The suite of pesticides to be targeted for quantification and their physical and chemical 
properties, 

• Range of air concentrations expected, 

• Minimum detection and quantification limits required, 

• Availability of validated methods for the pesticides of interest, 

• Available performance data (accuracy, precision, detection limits) for the method, 

• Required sampling volumes and sampling duration. 

Information that can be used to select sampling and analysis methods is available in the 
scientific literature, ASTM (2000a), and in U.S. EPA (1999b) methods. Information on pesticide 
sampling methods for measurements in occupational settings is available in publications by 
NIOSH (1994), OSHA (2000), and manufacturers of samplers and sorbent media. However, 
researchers conducting exposure measurements in residential and daycare environments should 
recognize that the methods developed to measure occupational exposure may not be sufficiently 
sensitive to measure the lower concentrations often encountered in non-occupational 
environments. 

The performance of the sampling and analysis method needs to be fully evaluated prior to 
use in field studies. As discussed previously, method detection limits must be sufficiently low 
for measurements in residences and daycares. Typically, detection limits for analysis of 
pesticides by GC/MS can be expected to be in the range of 5 to 50 ng/m 3 , which varies by 
compound and sample collection volume. Precision should be ± 25% and the accuracy, 
expressed as the percent recovery of spiked samples, should be in the range of 75 to 125%. 

Users of the methods also need to determine the sampling and retention efficiency of the sorbent 
media for the target pesticides. Sampling efficiency is the ability of the sampling medium to trap 
the pesticides of interest (ASTM, 2000a). Retention efficiency is the ability of the sampling 


39 


medium to retain the compound of interest. Methods for determining sampling and retention 
efficiencies are described in ASTM practice D4861 (ASTM, 2000a). This practice lists sampling 
and retention efficiencies for a number of organochlorine and organophosphorous pesticides and 
for a few pyrethroids collected on PUF. However, there are limited data on performance 
characteristics for many of the pyrethroids. 

The selection of the indoor sampling locations is contingent on the study objectives. 
Measurements of pesticide concentrations in the rooms where pesticide applications have been 
performed recently may provide an estimate of the highest potential exposure. But, 
measurements in locations where children spend the majority of their time may provide more 
accurate exposure estimates. The concentrations of pesticides in the air of a residence or daycare 
may vary substantially in different parts of the building following pesticide applications. Lewis 
et al. (2001) observed concentrations of diazinon in a bedroom that were less than one-third the 
concentrations measured in the room of application on the day following application. The 
difference between the rooms was even greater on the following days. Spatial differences may 
require measurements in more than one location in a residence or daycare to obtain accurate 
estimates of inhalation exposure. This may be cost prohibitive in large field studies. Therefore, 
emphasis should be placed on identifying the location where the child has the highest potential 
for exposure due to proximity to a source, activities (crawling, playing with pet, eating, etc.) or 
time spent in a location (i.e. living room, play ground, bedroom etc.). Outdoor sampling 
locations should be selected that are representative of the areas where the child spends time 
outdoors. Samplers should not be placed immediately adjacent to buildings where pesticides 
may be used or stored. 

5.5 Exposure Factor/Activity Pattern Information 

To estimate inhalation exposure, information must be collected to describe the (1) child, 
(2) microenvironments occupied by the child, and (3) the child’s activity while in those 
microenvironments. 

The minimum information required to characterize the child is the child’s age, weight, 
and gender. These variables are used to estimate inhalation rates. 

Information on the child’s location (microenvironment) and activity need to be recorded 
throughout the measurement period. For individual measurement assessments, the total time 
spent at each level of activity in each microenvironment must be recorded. For studies currently 
being performed in the NERL Human Exposure Analysis Branch, four microenvironments have 
been defined: indoors at home, outdoors at home, indoors at daycare centers, and outdoors at 
daycare centers. These four microenvironments are assumed to provide a reasonable estimate for 
inhalation exposure for young children (under age 4). Four macroactivities have been defined for 
this age group: active play, quiet play, sleeping/napping, and eating. An activity diary (Figure 5- 
1) is used for recording the activities in these microenvironment/macroactivity combinations. 


40 


Figure 5-1. Example of one page of the Indoors at Home section of a 24-h time-activity diary for estimating inhalation and dermal 
exposure of young children ___ 


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LS=long-sleeves; SS=short-sleeves; P=pants; S=socks; SH=shorts; N=naked 



















































The diary also collects information on clothing level and the type of surface in the 
microenvironment, information needed for dermal exposure estimates. The diary includes 
multiple pages, one each for indoors at home, outdoors at home, indoors at daycare, and outdoors 
at daycare and covers a 24-h monitoring period. Activities must be recorded by the parent or 
caregiver of the child. For the most accurate data collection, activity should be recorded on a 
continuous basis during the 24-hour measurement period. However, data collection by recall 
may be suitable if the parent or caregiver is provided with adequate instructions at the start of the 
measurement period and is aware of the need to record the data at a later period. Recall periods 
should be kept relatively short, generally no longer than 24 hours. Although, parents and 
caregivers can provide reasonably accurate data on the location of the 

child in the four microenvironments, they may have difficulty defining active versus quiet play. 
Therefore, it is important to provide training to the parent or caregiver on how to determine what 
to record for the child’s activity. To improve estimates of inhalation rates, researchers may want 
to define additional levels of activity. However, if additional levels of activity are defined, 
additional training of the parent or caregiver will be required. A videotape of children’s different 
activity levels may be used for that purpose. 

5.6 Estimation of Inhalation Rates 

Inhalation rates for children are highly variable and are a function of the child’s age, 
weight, and activity. The actual inhalation rates are not routinely measured in individual 
measurement studies. As an alternative, information on the child’s activities is collected during 
field measurement studies and used to estimate inhalation rates. 

Ranges of inhalation rates for children developed by NERL (McCurdy, 2001) using 
available measurement data are presented in Tables 5-2 and 5-3. The data presented in the tables 
should be used to calculate inhalation rates based on children’s age and weight. Data used to 
compile the ranges of inhalation rates shown in the tables are the same as those used by the EPA 
in the Exposure Factors Handbook (U.S. EPA, 1997a) and the Child-Specific Exposure Factors 
Handbook (U.S. EPA 2000c). 

Inhalation rates for short-term exposures of children under age 18 are presented in the 
Child-Specific Exposure Factors Handbook. But they are based only on the activity levels and 
do not account for the child’s age or weight. The recommended rates from the handbook for 
children 18 years of age and under are: 

• Rest: 0.3 m 3 /h, 

• Sedentary Activities: 0.4 m 3 /h, 

• Light Activities: 1.0 m 3 /h, 

• Moderate Activities: 1.2 m 3 /h, and 

• Heavy Activities: 1.9 m 3 /h 


42 



Table 5-2. Ranges of Inhalation Rates (V E ) for “Normal” Female Children and Adolescents on a 


per Body Mass Basis by Generalized Type of Activity (L min' 1 kg 1 ) 


Age 

Sleep/Nap 

/Rest 

Sedentary/ 
Sitting Quietly 

Light Activity 
/Walking 

Moderate 

Activity 

/Jogging 

Vigorous 

Activity/ 

Running 

1 

0.17-0.20 

0.21-0.26 

0.27 - 0.69 

0.70-1.05 

1.06-1.25 

2 

0.16-0.19 

0.20 - 0.25 

0.26 - 0.68 

0.69-1.04 

1.05-1.26 

3 

0.15-0.18 

0.19-0.23 

0.24 - 0.67 

0.68-1.03 

1.04-1.27 

4 

0.14-0.17 

0.18-0.22 

0.23 - 0.66 

0.67-1.02 

1.03-1.28 

5 

0.14-0.16 

0.17-0.21 

0.22 - 0.65 

0.66-1.01 

1.02-1.29 

6 

0.13-0.15 

0.16-0.20 

0.21-0.64 

0.65-1.00 

1.01 -1.30 

7 

0.12-0.14 

0.15-0.18 

0.19-0.63 

0.64 - 0.96 

0.97-1.32 

8 

0.11 -0.13 

0.14-0.17 

0.18-0.60 

0.61-0.93 

0.94-1.33 

9 

0.10-0.12 

0.13-0.16 

0.17-0.59 

0.60 - 0.92 

0.93-1.34 

10 

0.10-0.12 

0.13-0.15 

0.16-0.57 

0.58-0.91 

0.92-1.36 

11 

0.09-0.11 

0.12-0.14 

0.15-0.53 

0.54 - 0.87 

0.88-1.35 

12 

0.09-0.10 

0.11-0.13 

0.14-0.50 

0.51-0.83 

0.84-1.35 

13 

0.08-0.10 

0.11-0.13 

0.14-0.49 

0.50-0.80 

0.81 -1.36 

14 

0.08 - 0.09 

0.10-0.12 

0.13-0.48 

0.49 - 0.78 

0.79-1.37 

15 

0.08 - 0.09 

0.10-0.11 

0.12-0.47 

0.48 - 0.76 

0.77-1.38 

16 

0.07 - 0.08 

0.09-0.10 

0.11-0.44 

0.45 - 0.73 

0.74-1.38 

17 

0.07 - 0.08 

0.09-0.10 

0.11-0.43 

0.44-0.71 

0.72-1.38 

18 

0.06 - 0.07 

0.08 - 0.09 

0.10-0.42 

0.43 - 0.69 

0.70-1.38 


Notes: 1. These data should only be used for "normal" children and adolescents. Different estimates are 

needed for obese, underweight/sickly kids, as well as children/adolescents who are very fit due to 
partaking in frequent and "heavy" exercise. 

2. To obtain activity-specific V E (in L), simply multiply the estimate shown above by time spent in 
each category (in minutes) and also by body weight (in kg) of the child/adolescent in question. These 
values can then be converted into m 3 per whatever time period is of interest by multiplying 

by the appropriate unit conversions. 

3. The values shown have been "smoothed" to minimize abrupt jumps by age. The data within a range 
for each activity level probably are distributed log-normally, but definitive information on this 
distribution is scanty. The upper bound of the "Vigorous" class is the same as V EMax , and it cannot be 
maintained more than approximately 5 minutes before it declines over time; see Bink (1962) and Erb 
(1981). 

Sources: U.S. EPA (2000c), U.S. EPA (1997a), and McCurdy (2001) 


43 












Table 5-3. Ranges of Inhalation Rates (V E ) for “Normal” Male Children and Adolescents on a 


per Body Mass Basis by Generalized Type of Activity (L min' 1 kg' 1 ) 


Age 

Sleep/Nap 

/Rest 

Sedentary 
/Sitting Quietly 

Light Activity 
/Walking 

Moderate 

Activity 

/Jogging 

Vigorous 

Activity 

/Running 

1 

0.18-0.21 

0.22 - 0.27 

0.28 - 0.74 

0.75- 1.13 

1.14-1.76 

2 

0.17-0.20 

0.21-0.26 

0.27 - 0.74 

0.75-1.13 

1.05-1.77 

3 

0.16-0.19 

0.20 - 0.24 

0.25 - 0.73 

0.74-1.12 

1.04-1.78 

4 

0.15-0.18 

0.19-0.23 

0.24 - 0.72 

0.73-1.12 

1.13-1.79 

5 

0.14-0.17 

0.18-0.21 

0.22-0.71 

0.72-1.11 

1.12-1.80 

6 

0.14-0.16 

0.17-0.20 

0.21-0.70 

0.71 - 1.10 

1.11 - 1.81 

7 

0.13-0.15 

0.16-0.19 

0.20 - 0.69 

0.70-1.05 

1.06-1.83 

8 

0.12-0.14 

0.15-0.17 

0.18-0.64 

0.65-1.04 

1.05-1.77 

9 

0.11-0.13 

0.14-0.16 

0.17-0.64 

0.65-1.03 

1.04- 1.72 

10 

0.11-0.13 

0.14-0.15 

0.16-0.63 

0.64-1.00 

1.01 - 1.64 

11 

0.10-0.12 

0.13-0.15 

0.16-0.59 

0.60 - 0.95 

0.96-1.59 

12 

0.09-0.11 

0.12-0.13 

0.14-0.57 

0.58 - 0.94 

0.95-1.56 

13 

0.09-0.10 

0.11-0.12 

0.13-0.56 

0.57 - 0.93 

0.94- 1.50 

14 

0.09-0.10 

0.11-0.12 

0.13-0.55 

0.56 - 0.90 

0.91 - 1.47 

15 

0.08 - 0.09 

0.10-0.11 

0.12-0.53 

0.54-0.89 

0.90-1.44 

16 

0.07 - 0.08 

0.09-0.10 

0.11-0.52 

0.53 - 0.88 

0.89-1.42 

17 

0.07 - 0.08 

0.09-0.10 

0.11-0.51 

0.52-0.87 

0.88-1.39 

18 

0.07 - 0.08 

0.09 - 0.09 

0.10-0.51 

0.52 - 0.86 

0.87-1.38 


Notes: 1. These data should only be used for "normal" children and adolescents. Different estimates are 
needed for obese, underweight/sickly kids, as well as children/adolescents who are very fit due 
to partaking in frequent and "heavy" exercise. 

2. To obtain activity-specific V E (in L), simply multiply the estimate shown above by time spent in 
each category (in minutes) and also by body weight (in kg) of the child/adolescent in question. These 
values can then be converted into m 3 per whatever time period is of interest by multiplying 

by the appropriate unit conversions. 

3. The values shown have been "smoothed" to minimize abrupt jumps by age. The data within a range for 
each activity level probably are distributed log-normally, but definitive information on this distribution 

is scant. The upper bound of the "Vigorous" class is the same as V EMax , and it cannot be 
maintained more than approximately 5 minutes before it declines over time; see Bink (1962) and 
Erb (1981). 

Sources: U.S. EPA (2000c), U.S. EPA (1997a), and McCurdy (2001) 


44 






These inhalation rates are within the range of rates presented in Tables 5-2 and 5-3. But more 
accurate estimates of inhalation exposure can be made using the range of rates presented in the 
tables for calculations based on the child’s age and weight. 


45 


6.0 MACRO ACTIVITY APPROACH FOR ESTIMATING DERMAL EXPOSURE 


6.1 Introduction 

Data on children’s exposures and activities are currently very limited and insufficient to 
support quantitative assessments that do not rely heavily on major default assumptions. Results 
derived from an initial assessment of critical exposure pathways and factors for assessing 
children’s residential exposures to pesticides indicate that dermal exposure and indirect 
nondietary ingestion exposure may result in high residential exposures for children (Cohen Hubal 
et al. 2000). 

Two main approaches are currently used to assess dermal exposure. These assessment 
approaches provide different ways of integrating exposure over time and space. In the 
macroactivity approach, exposure is estimated individually for each of the microenvironments 
where a child spends time and each macroactivity that the child conducts within that 
microenvironment. To do this, exposure is modeled using empirically derived transfer 
coefficients to aggregate the mass transfer associated with a series of contacts with a 
contaminated medium. In the microactivity approach, exposure is explicitly modeled as a series 
of discrete transfers resulting from each contact with a contaminated medium. The algorithm and 
data requirements for the microactivity approach were described briefly in Section 3.3.2. 
However, as discussed in that section, implementation of the microactivity approach is not 
practical in large exposure field studies. Therefore, details of the approach are not discussed in 
this protocol. This section describes the macroactivity approach for estimating dermal exposure. 

6.2 Summary of Data Requirements 

To estimate exposure using the macroactivity approach, microenvironments are defined 
by location and surface type. Activity- and microenvironment- specific transfer coefficients are 
developed in laboratory experiments or controlled field studies. Exposure can then be estimated 
individually for each of the microenvironments where a child spends time and each macroactivity 
that the child conducts within that microenvironment using information on surface loadings, the 
empirically-derived transfer coefficients, and information on the amount of time in that 
microenvironment/macroactivity. The dermal exposure algorithm and data requirements are 
presented in Table 6-1. 

6.3 General Considerations 

Numerous data must be considered for each microenvironment/macroactivity 
combination when estimating dermal exposure. These data include: definitions of the 
microenvironments/macroactivities that are important for dermal exposure; surface loadings 
(total or transferable) of pesticides or chemicals for each microenvironment/macroactivity 
combination; amount of time a child spends in each microenvironment/macroactivity during a 


46 


Table 6-1. Data Requirements for Estimating Dermal Exposure With the Macroactivity 
Approach _ 


Parameter 

Measurement 

How Collected 

Units 

Dermal Exposure - Macroactivity approach 

^dme/ma (^-'surfXTC me / ma )(AD me y ma ) 

^surf 

Surface loading (total or 
transferable) in the me 

Measure with C 18 surface press 
sampler, PUF roller, surface 
wipe, or soil sample 

pg/cm 2 

TC 

'-'me/ma 

Transfer coefficient 

Empirically determined for 
each me/ma from laboratory or 
field studies 

cm 2 /h 

^^me/ma 

Exposure duration based on 
location, activity level, 
clothing 

Time-activity diary, 
questionnaire 

h/d 


24-h period; and, the transfer coefficient for each microenvironment/macroactivity. These data 
considerations affect the subsequent sampling considerations. Each consideration is discussed 
more fully in the following paragraphs. Table 6-2 lists the various microenvironment 
/macroactivity combinations that are applicable to the exposure scenario described in Section 4. 

For each microenvironment/macroactivity combination, the surface loading of the 
chemical must be determined. For recent pesticide applications, the assumption, based on 
limited field data, is that the pesticide surface loading is not homogeneous in the residential or 
daycare center environment. In order for the measurements that are collected to be most 
applicable and representative of the child’s environment, it is important to determine those 
locations where the child spends the most time in the residential or daycare center environment 
and sample accordingly. For each home or daycare center, measurements will be made for only 
those surfaces for which the child is expected to have substantial contact. This sample 
measurement can be collected using the C 18 surface press sampler, a PUF roller, surface wipe, or 
for outdoor locations to collect a soil or turf sample. 

For each microenvironment/macroactivity combination, the amount of time the child 
spends in each combination must be determined. These data are collected using time-activity 
diaries or questionnaires. 


47 















Table 6-2. Microenvironment/Macroactivity Combinations for Estimating Dermal Exposure 


Location 

Surface 

Activity 

Eating 

Sleeping/ 

napping 

Quiet play 

Active play 

Indoor at home 

Carpet 

X 

X 

X 

X 

Hard surface 

X 

X 

X 

X 

Upholstered 

fumiture/bedding 

X 

X 

X 

X 

Outdoor at home 

Grass 

X 

X 

X 

X 

Soil 

X 


X 

X 

Pavement 

X 


X 

X 

Indoor at daycare 

Carpet 

X 

X 

X 

X 

Hard surface 

X 

X 

X 

X 

Upholstered 

fumiture/bedding 

X 

X 

X 

X 

Outdoor at daycare 

Grass 

X 

X 

X 

X 

Soil 

X 


X 

X 

Pavement 

X 


X 

X 


The transfer coefficients for each microenvironment/macroactivity must also be 
determined. These are data that are currently not available and need to be generated 
experimentally in the laboratory or carefully controlled field experiments. This is discussed more 
fully in Section 6.6, Estimation of Transfer Coefficients. 

Environmental monitoring methods for assessing dermal exposure have few equipment 
considerations, as compared to the inhalation route. However, the concentrations associated with 
each sample are dependent on the locations sampled and the sampling method used. Pesticide 
distributions in the residential environment are not homogeneous which may result in significant 
concentration differences in adjacently sampled areas potentially leading to an over or 
underestimation of exposures depending on the representativeness of the sampling locations. For 
this reason, the appropriate sampling locations, sampling methods that address various surface 


48 

























types, and the number of samples required to provide representative information must all be 
considered. Outlined below are issues that should be considered when assessing the dermal 
route of exposure as a component of a large field study: 

• Surface sampling methods should be matched to the sampling method that was used to 
generate the transfer coefficients. For example, transferable residue measurements should 
be collected using a C ]8 surface press sampler method if the C 18 surface press sampler 
method was used to generate the transfer coefficient. 

• Methods of collection should be appropriate for the types of surfaces being monitored. 

For example, surface wipe samples should be collected from hard surfaces and not from 
carpets or other fabric surfaces. 

• When possible, multiple individual samples (at least three) should be collected from 
various areas in the microenvironment where the child is in contact with surfaces. 
Analyzed individually, these samples will provide information regarding the distribution 
of pesticides in the microenvironment; when the results are combined, they provide an 
average value to help minimize under or overestimation of surface loadings, and thus, 
exposure. 

• Locations for monitoring and sample collection should be selected that are representative 
of where the child spends his/her time. Locations targeted for monitoring should be 
consistent with the study objective. Avoid monitoring locations that may bias the results 
such as points of application or near sources of potential contamination unless they are 
part of the study design. 

• To reduce analytical costs, it may be possible to collect aggregate samples (e.g., surface 
press), or combine samples (e.g., surface wipes) prior to analysis to obtain “average” 
concentrations. 

• Be cognizant of the potential damage that sampling methods may pose to personal 
property. For example, isopropanol used during the collection of surface wipe samples 
can cause damage to wood finishes or other sensitive surfaces; therefore, samples should 
not be collected from surfaces that would be damaged by the collection method. 

6.4 Monitoring Methods 

As discussed above in General Considerations, the loadings of pesticides on surfaces 
associated with each of the microenvironment/macroactivity combinations that a child comes 
into contact with are essential data for estimating dermal exposure. However, since it is 
impossible to measure the pesticide loadings for all surfaces in all situations, surface loadings are 
measured for only those areas for which children are expected to have substantial dermal contact. 
It is extremely important that the surfaces that are sampled are representative of the surfaces for 
which the child may have appreciable contact during his/her various activities. These areas would 
include indoor surfaces, either at home or in a daycare center, such as floors and furniture, as 
well as outdoor surfaces such as grass, soil, and pavement. Floors include both carpeted areas 
and hard surface areas such as vinyl, tile, or wood. Furniture can be categorized as upholstered 


49 


(fabric) or hard (metal, vinyl, wood) surfaces. These previously mentioned microenvironment 
locations are specific to the exposure scenario as defined in Section 4. It should be recognize 
that other locations may be of equal, or greater importance for other exposure scenarios. For 
example, the interior of motor vehicles may be an important microenvironment in agricultural 
areas due to spray drift from pesticide applications on crops. Exposure to pesticides bound to 
settled dust on the seats or other interior surfaces of a vehicle may be a source of exposure. 

Measurements to determine surface loadings can be divided into two categories: those 
representing the total amount of pesticide residue present on a surface and those representing the 
amount of pesticide residue that is available for transfer (i.e., transferable residues). Methods for 
estimating total pesticide residues include the collection, extraction, and analysis of upholstery 
fabrics, carpet, and soil samples. Transferable residues can be estimated by collecting and 
analyzing surface wipe, surface press or roller samples. These latter methods provide an 
estimate of the amount of each pesticide that is available for transfer from one surface to another. 
The methods used must be appropriate to the type of surface to be sampled. 

The transferable residue measurement methods do not necessarily simulate the contact 
that a child may make with the surface being sampled and should not be considered surrogate 
exposure methods. It is not feasible to simulate all of the skin surfaces of a child that may 
contact surfaces in the microenvironment. A child may contact a surface with the feet, knees, 
legs, bottom, arms, hands, or face. Skin surfaces may be dry, wet, or sticky. Rather than 
attempting to simulate these skin surfaces, the approach has been to use a method to measure 
transferable residues on the surfaces in conjunction with transfer coefficients to estimate dermal 
exposure. As discussed previously, the transfer coefficients must be developed in laboratory 
tests or under carefully controlled field experiments. The transfer coefficients must be developed 
using the same method for measuring surface loading as is used in the field measurement studies. 
Transfer coefficients can be developed for a wide variety of microenvironment/macroactivity 
combinations, hard and soft surfaces, as well as dry, wet, and/or sticky skin. 

Brief descriptions of some of the more common methods developed for estimating total 
and transferable pesticide residues are discussed below. 

PUF Roller . The PUF roller method is designed to estimate transferable residues from 
carpeted or hard flooring surfaces (Camann et al., 1996). It has also been used to measure 
transferable residues from outdoor surfaces such as turf (Nishioka, et al., 1999). It is described in 
ASTM Standard Practice D6333 (ASTM 2000b) and consists of a polyurethane foam sleeve 
roller attached to an aluminum frame of specified dimensions and weight. The foam sleeve is 
rolled across a specified area of the surface being monitored at a specified pressure (6900 to 8600 
Pa). The foam sleeve is removed, solvent extracted and analyzed for pesticides by GC/MS, 
GC/ECD, or other suitable instrumental method. 

Drag Sled . The Drag Sled sampler is designed to estimate transferable residues from 


50 




floor surfaces (Vaccaro and Cranston, 1990). The sampler consists of a 7.6 cm x 7.6 cm x 1.9 
cm block of wood or other material that holds a 10 cm x 10 cm piece of denim cloth as the 
sampling media. With the denim cloth in contact with the flooring surface, a weight is applied to 
the block to provide a specified pressure (4500 Pa). The device is pulled at a specified rate 
across the floor area. The denim cloth is removed, extracted, and analyzed for pesticides by 
GC/MS, GC/ECD, or other suitable instrumental method. This method has not been used 
extensively. 

California Roller . The California Roller, described by Ross et al. (1991), is designed to 
estimate transferable residues from indoor and outdoor surfaces. The sampler consists of a large 
weighted roller that uses polyester-cotton percale bedding material as the sampling media. The 
roller is a large cylinder (13 cm OD, 63 cm in length) constructed of polyvinyl chloride pipe, 
partially filled with steel shot to provide a specified pressure (2300 Pa), and is covered with a 1 
inch foam cushion. The polyester-cotton percale material is placed directly in contact with the 
flooring surface to be sampled , a sheet of plastic is placed on top of the cloth and the roller is 
rolled over the plastic/cloth. The cloth is solvent extracted and analyzed for pesticides by 
GC/MS, GC/ECD, or other suitable instrumental method. The original method has been 
modified and its performance has been compared to other methods (Fortune, 1997). The method 
has been used most extensively by pesticide registrants. 

Surface Press or Mechanical Press . The surface press or mechanical press method is used 
to estimate transferable residues from hard and soft surfaces. Currently, a sampler based on the 
design of the EL press sampler (Edwards and Lioy, 1999) is being evaluated in pilot studies by 
NERL. In general, this method consists of a block shaped device constructed of Delrin polymer 
and uses C 18 impregnated Teflon extraction disks (3M Empore® disks) as the sample collection 
media. Other collection media are being considered but have not been fully evaluated at this 
time. The surface press sampler holds two C 18 disks while providing a specific contact area (114 
cm 2 ) and contact pressure (~1200 Pa). Once the disks are loaded into the sampler the sampler is 
placed on the surface to be monitored and allowed to remain in contact for a specified period of 
time. The C 18 disks are then solvent extracted and analyzed for pesticides by GC/MS, GC/ECD, 
or other suitable instrumental method. 

Surface Wipe. Surface wipe methods are used to estimate the surface pesticide residue 
loading on hard surfaces such as floors, furniture, window sills, counters, toys, and other surfaces 
and objects a child may contact. Surface areas being sampled must be non-porous and relatively 
smooth in texture. There are several methods that have been developed but all are similar in that 
a material, generally cotton gauze or some filter material, often wetted with a solvent 
(isopropanol or water), is used to wipe a specified surface area (Wright et al., 1993; Camann et 
al., 1996; Lioy et al., 1998; Lu and Fenske, 1999). The collection material is then extracted and 
analyzed for pesticides by GC/MS, GC/ECD, or other suitable instrumental method. 

Selection of practical, representative surfaces for monitoring can be one of the most 


51 





difficult issues associated with the collection of environmental samples for the estimation of 
children’s dermal exposures. Financial and physical resources generally limit the number of 
samples that can be collected and analyzed at any one location making those that are collected 
critical to the success of the study. Children contact a wide variety of surfaces during their 
activities and, as previously discussed, the level of activity, surface type, and the number of 
surface contacts are all important variables. While the study design and field sampling protocols 
can define the appropriate criteria, the general surface types, and the general sample collection 
locations, the ultimate decision for sample collection is the responsibility of the field sampling 
personnel and relies to a great extent on their experience and training. Each home or daycare 
center situation requires decisions to be made that are specific to that particular home or daycare 
center and the activities of the children in those locations. The following are some general 
guidelines for determining appropriate sampling locations. The area and surfaces sampled 
should be: 

• representative of where the child spends the majority of his/her time while awake, 

• representative of the surfaces that the child frequently comes in contact with, 

• amenable to the designated methods of sampling, and 

• surfaces for which empirically-derived transfer coefficients are available. 

Information pertaining to the first two guidelines is generally obtained through discussions with 
the child’s caretaker and/or by observation of the child’s activities. Questionnaires can also be 
developed to provide a systematic approach to defining the areas and surfaces appropriate for 
sampling. 

The preceding paragraphs provided a brief overview of the generally available methods 
for measuring pesticide residue surface loadings. In NERL’s children’s exposure measurement 
studies, the most commonly used methods to measure surface pesticide residue loadings are 
surface wipes and the C 18 surface press sampler. The following is a more detailed discussion of 
these methods. 

The surface wipe method used in the recent NERL children’s exposure studies uses 4-in x 
4-in, 6-ply, cotton dressing sponges wetted with pesticide grade isopropanol as the collection 
media. The surface to be sampled is wiped with an isopropanol dampened dressing sponge in 
one direction while frequently exposing a fresh surface of the wipe. The surface is then wiped in 
a perpendicular direction with the same wipe. Once this is complete, the first wipe is placed in a 
storage container and a second wipe is prepared and the process is repeated with this second 
wipe. The second wipe is added to the container holding the first wipe. Samples are stored 
frozen (-20 °C) and analyzed by solvent extraction followed by GC/ECD, GC/MS, or other 
appropriate analytical method. 

A total sampled area of 930 cm 2 , representing an area with dimensions of 30.5 x 30.5 cm 
(12x12 inches), is generally sampled when collecting samples from a flat surface. Other areas 


52 


may also be used to accommodate spaces available. The area sampled for irregular shaped 
surfaces may be measured and determined on an individual basis. Smaller surfaces may be used 
if high concentrations are suspected or if there is limited area available for sampling. The actual 
surface area sampled must be determined and recorded. This method should not be used on 
surfaces that may be damaged by alcohol. 

The surface press method used in recent NERL children’s exposure studies consists of a 
specially constructed sampling device and utilizes C ]8 extraction disks (3M Empore) as the 
transfer/collection medium. The sampler is based on the design of the sampler described by 
Edwards and Lioy (1999). Two 90 mm,C 18 extraction disks are mounted in a specially 
constructed sampling device constructed of Delrin polymer and having a total mass of 1340 g. 
The two disks provide a net surface contact area of 114 cm 2 and a contact pressure of 11.8 g/cm 2 . 
The disks are secured in the surface press sampler by means of a clamping system and during use 
are placed in direct contact with the surface being tested. The press sampler is left in contact 
with the surface for a prescribed period (generally 2 or 5 minutes) after which time it is lifted 
from the surface and the disks carefully removed, folded, and placed in a pre-cleaned and 
labeled, glass storage container. Samples are stored frozen (-20 °C) and analyzed by solvent 
extraction followed by GC/ECD, GC/MS, or other appropriate analytical method. Testing is on¬ 
going in NERL to finalize the procedures for use of this method for a wide range of current use 
pesticides, particularly for the pyrethroids. 

It should be recognized that selection of the extraction and analysis methods for use with 
these sampling media is critical to successful measurements of surface loading. Because of the 
low surface loadings that may be encountered in residences and daycares, the extraction method 
must have high recovery of the target compounds and the method detection limits must be 
sufficiently low. Levels of pesticides measured in households are generally very low. In a recent 
study, transferable residue concentrations measured from carpet with a PUF roller were in the 
range of 0.03 to 0.61 pg/m 2 in a room with a recent application of diazinon (Lewis et al., 2001). 
There are many factors that ultimately guide the selection of sampling and analysis methods. 
Among them are the sensitivity of the analytical instrument that will be used for the analysis of 
the extract, the type of analytical detector, the final volume to which the sample extract is 
concentrated, loading or concentration of the target compounds on the original sampled surface, 
and the transfer efficiency of the target compounds from the surface to the sampling media. All 
of the above parameters can be optimized by conducting pilot or scoping studies to field test 
methods for the pesticides of interest before a large field study is conducted. Although 
previously collected samples can initially be screened and the extracts adjusted by concentrating 
or diluting specific samples to insure that they fall within the analytical range, this is not advised 
due to the additional handling and potential associated errors as well as the inefficiency of 
multiple analyses of the same sample. In general, liquid injections of extracts on a GC/MS 
system will be measurable in the low pg/pL (ng/mL) range while operating in the selective ion 
mode and, therefore, an injected sample must be in this range to be measurable. If an area of 930 
cm 2 is wiped using the surface wipe method, the sample extract is concentrated to a final volume 


53 


of 1.00 mL, and the transfer efficiency is near 100%, the initial surface concentration must be 
approximately 11 pg/cm 2 (0.11 pg/m 2 ) in order to be measurable. Increasing the sampled surface 
area, concentrating the extract to a smaller volume, or optimizing the instrument are all viable 
steps to decreasing the detection limit. It should be noted that simply increasing the size of the 
sampled area may not be sufficient to increase the measurable pesticides since detection of the 
pesticides may also be affected by interferences associated with the sampled area. Precision for 
the surface press and surface wipe samples should be ± 25% for duplicate samples and the 
accuracy, expressed as the percent recovery of spiked samples, should be in the range of 75 to 
125%. ’ 


6.5 Exposure Factor/Questionnaire Information 

The numerous data parameters that need to be considered when estimating dermal 
exposure were described above. Exposure factors are used in conjunction with the 
environmental measurement data to estimate exposure. Collection of exposure factor 
information is often accomplished through the use of activity diaries and questionnaires. 
Questionnaires break the day into discrete time periods of interest. Activity diaries can provide 
information as a function of time over the entire day. At a minimum, the diaries and 
questionnaires must include a notation of the time period of interest, indoor versus outdoor 
activities during this time period, clothing levels, and microenvironment/macroactivity 
information. Table 6-3 shows the microenvironments/macroactivity combinations and surfaces 
for which information is collected. An example of a time-activity diary that can be used to 
collect the exposure factor information required when assessing dermal exposure using the 
macroactivity approach and information for estimating inhalation exposure was depicted in 
Figure 5-1 in Section 5.5. 

6.6 Estimation of Transfer Coefficients 

The transfer coefficient for each microenvironment/macroactivity must be empirically 
determined from controlled laboratory experiments or field studies. In laboratory studies, 
experiments can be designed to develop transfer coefficients for a variety of micro¬ 
environment/macroactivity combinations. In field studies, transfer coefficients are determined 
for a discrete period of time for a single microenvironment/macroactivity combination. For 
children, it is necessary to record activity patterns (i.e., contact activities, activity level, amount 
of clothing, locations), collect dermal wipes (i.e., based on exposed skin and activity 
information), and measure transferable surface residue loadings (i.e., from the location where the 
child spends the majority of his/her time). As an alternative to the dermal wipes, cotton 
dosimeters may be worn in a specific microenvironment/macroactivity for a defined period of 
time. These collected parameters can then be substituted into the equation to calculate the 
transfer coefficient. 

The transfer coefficient, TC me/ma , provides a measure of dermal exposure resulting from 


54 


Table 6-3. Microenvironments/Macroactivity Combinations and Surfaces for Which Activity 
Data Are Collected 


Microenvironment 

Macroactivity 

Active Play 

Quiet Play 

Sleeping 

Eating 

Indoors at Home 





-Carpet 





-Hard Floor 





-Upholstery/Bedding 





Outdoors at Home 





-Grass 





-Dirt/Soil 





-Paved Surfaces 





Indoors at Daycare 





-Carpet 





-Hard Floor 





-Upholstery/Bedding 





Outdoors at Daycare 





-Grass 





-Dirt/Soil 





-Paved Surfaces 






contact with a contaminated microenvironmental surface while engaged in a specific 
macroactivity. The transfer coefficient takes into account the fraction of the surface residue that 
is transferred from a surface to skin, the character of the microenvironmental surface that is 
contacted, and the area of the microenvironmental surface that is contacted during a time 
increment for a given activity. TC der can be defined as follows: 

TC me/ma = (E dme/ma ) /[(C surf )(AD me/ma )] (13) 


55 



























where 


TC 


me/ma 
''dme/ma 


'"'surf 

AD 


me/ma 


transfer coefficient for the microenvironment/macroactivity (cm 2 /h) 
dermal exposure for a given microenvironment/macroactivity combination 
over a 24-h period (pg/d) 

surface loading (total or transferable) measured in the microenvironment 
(Hg/cm 2 ) 

activity duration that represents the time spent in each micro¬ 
environment/macroactivity combination with a specific clothing pattern 
for the child that would affect the surface area available for transfer over a 
24-h period (h/d) 


The transfer coefficient relates to the specific type of pesticide residue loading measured. 
For example, if a transferable pesticide residue loading is measured, then the transfer coefficient 
is related to the transferable residue. However, if a total pesticide residue loading is measured, 
then the transfer coefficient must be related to the total residue. It is important to keep this 
distinction in mind when performing environmental measurements. The same sampling methods 
must be used both for the field surface loading measurements and in the experiments to 
determine the transfer coefficients for the same microenvironment/macroactivity combination. 


56 


7.0 


APPROACH FOR ESTIMATING DIETARY INGESTION EXPOSURE 


7.1 Introduction 

Total ingestion of pesticides by children from foods and beverages involves two major 
components: (1) directly ingested foods brought into the home or other eating places containing 
pesticide residues primarily from agricultural applications (i.e., dietary ingestion exposure, or 
simply dietary exposure), and (2) indirect ingestion exposures associated with additional 
contamination of foods during consumption by children. This section focuses on the first 
component and is termed dietary exposure because it is associated with pesticides that are 
inherent to the foods themselves, and not how they may be further contaminated by the activities 
of the child during consumption in the residential or other eating environment. Approaches for 
estimating indirect ingestion from foods, as well as other pathways of indirect ingestion exposure 
not associated with diet, are included in Section 8.0, Approach for Estimating Indirect Ingestion 
Exposure. 

For certain exposure scenarios (e.g., chronic exposures) and in the absence of recent 
pesticide applications, the dietary component of ingestion exposure is likely the dominant 
exposure pathway to pesticides, and potentially the most significant of all pathways for aggregate 
exposure. Such scenarios occur in particular when handling of foods by the child is minimal and 
when additional pathways of contamination, such as from surface deposits of residues resulting 
from outdoor air, track-in of particles, and/or indoor sources of pesticides, are minimal. Then, 
agricultural sources are typically the most significant sources of dietary, and hence aggregate 
exposure. 

Personal monitoring methodology for measuring dietary exposure of children is based on 
the duplicate diet method for collection of food samples from study subjects with subsequent 
measurement of pesticide residues in the collected food samples. These procedures provide the 
ability to measure the importance of diet relative to other pathways of personal exposure and they 
directly measure, with reasonable certainty, the exposure from all foods and beverages in the 
diets presented to the child during the monitoring period. Children’s diets differ significantly 
from those of adults and children eat more than adults relative to their body weights. The diet of 
newborns is limited exclusively to breast milk or formula, both of which may expose infants to 
significant concentrations of environmental contaminants (Mukerjee, 1998 and Chance et al., 

1998). Infants and young children eat more fruit and milk products in proportion to their body 
size and have a less varied diet than adults. In addition, there may be tremendous variability in 
diet among young children of similar ages and for a single child at different periods in time. 

Some infants and toddlers go through phases where only a few preferred foods are eaten for 
weeks and months at a time. Such a limited diet may potentially increase dietary exposure of 
young children to environmental contaminants such as pesticide residues in fruit (NAS, 1993 and 
Goldman, 1995). The numerous factors that influence the diets of young children and resulting 
health implications make it extremely important to accurately assess their dietary intake of 


57 


pesticides. 


7.2 Summary of Data Requirements 

Dietary exposure to a pesticide is defined as the amount of pesticide ingested in the foods 
and beverages consumed by a child over some reference exposure period, exclusive of any 
additional contamination occurring during the actual process of eating the foods, as discussed 
above. Thus, exposure to pesticides in drinking water may also be included in estimating dietary 
exposure. Depending on dietary collection objectives and economic considerations, foods may 
be collected and analyzed as independent items or collections of items that are combined for 
analysis. A summary of the data requirements for this approach is presented in Table 7-1. 


Table 7-1. Data Requirements for Estimating Dietary Ingestion Exposure 


Parameter 

Measurement 

How Collected 

Units 

E f = S C f W f 

f 

food item or collection of items 



Cf 

concentration of contaminant in 
food f 

Analyze food item or items 

Hg/kg 

w f 

weight of food f 

Weigh food item or items 

kg/d 


7.3 General Considerations 

Dietary samples are specific to the subject being monitored and are typically collected 
over intervals of one day, although other sample collection intervals may be used. Dietary 
samples can be collected for several consecutive days, several non-consecutive days, or at widely 
spaced times over weeks, months, or seasons. In most studies, the caregiver of the child will 
prepare a duplicate plate by measuring or estimating duplicate portions of each food given to the 
child. The portions are identical to those served to the child in all aspects of preparation, type of 
food, and amount of food. Following the eating activity by the child, portions are adjusted to 
account for foods not consumed, thus providing a duplicate diet sample. The distinction between 
a duplicate plate and a duplicate diet is typically more significant for children than adults because 
significant quantities of food may be left uneaten by the child. To accurately measure dietary 
exposure, samples must be collected for all foods and beverages consumed, including those 
obtained away from home at restaurants, schools, day cares, etc. The caregiver will often be 


58 

















responsible for recording a diary of the type and amount of each food the child consumes. 
Supplemental questions are answered by the caregiver that allow evaluation of both the 
completeness and representativeness of the collected sample, and hygiene and dietary habits of 
the child. Duplicate diet samples are often separated into solid foods and beverages during the 
monitoring period because of analytical and economical considerations. Drinking water can be 
included in the beverage samples or collected separately. Both samples (i.e., solids and 
beverages) are composited to create two samples for the monitoring period. This allows for an 
exposure estimate for the dietary pathway that is equivalent to other pathways being measured. 

In some studies, individual foods may be collected. This allows subsequent compositing in the 
laboratory which may allow for improved detection limits and/or selection of foods that are more 
likely to contain pesticide residues. 

Sample collection containers should be sufficiently large for the largest sample that might 
be collected or multiple containers must be provided. Container materials should neither add the 
contaminant of interest (or analytical interferences) to the food sample nor cause losses of the 
contaminant of interest from the collected foods. Containers should be made of materials that 
will withstand transport, handling, and in some cases, freezing. Storage and transport of samples 
are normally important parameters to prevent sample spoilage during collection. Samples should 
be stored and shipped refrigerated or frozen. 

7.4 Monitoring Method 

To monitor dietary ingestion exposure of children, the duplicate diet methodology is 
used. This is a well established method that has been used in several monitoring studies (Berry, 
1997, Thomas et al., 1997, and Melnyk et al., 1997). Since children are the targeted subjects, 
caregivers are trained to collect and record information on duplicates of foods consumed using 
visual estimation procedures. Specifics of the sample collection are determined in the study 
design prior to field activities. NERL has developed a dietary model and database system 
(DEPM, Tomerlin et al., 1997) to assist in designing dietary monitoring studies and interpreting 
the results of composite diet sampling. The DEPM includes both consumption and pesticide 
residue data from existing notional monitoring programs. Consumption information for children 
is included. DEPM uses historical food information to estimate total daily intake of pesticides, 
and food groups and items that are major contributing factors to dietary exposure. DEPM is 
available at http://www.epa.gov/nerlcwww/depm.htm. 

Typically, analyzing composited food samples is an integral part of determining dietary 
exposure. All methods for collection, storage, mixing, extraction, and analysis should be 
selected and implemented in such a way that they provide residue concentration data that are of 
known and acceptable quality for meeting the overall study objectives. Composited food 
samples present unique analytical challenges because the samples are very diverse and may 
contain varying amounts of fats and other interfering substances. In most cases, relatively few of 
the individual food items in a composited sample contain residues. While these residues may or 


59 



may not be present at high levels in the individual food item, the compositing process dilutes 
them by combining the contaminated item or items with a large mass of food which does not 
contain any residues. Thus, sensitivity of the analytical method for foods is extremely important. 

Diet is often the limiting pathway in multi-pathway assessments due to the relative 
sensitivity of food analytical methods versus those for other media. A typical diet (even for a 
child) may result in collection of 100 tO 500 g/d for composite solid food or beverage samples. 
Typically, 25 g is the maximum practical aliquot for analysis. This limitation allows for the 
analysis of only 5 to 25% of the total daily solid food or beverage sample. Analysis of other 
media is not subject to such sample size limitations and it is possible to analyze the entire sample 
collected in a one day period, and in some cases, even longer. Even with equivalent analytical 
sensitivity among media, overall method detection limits are 10 - 100 times higher for food than 
for other media due to relative amount of the daily sample analyzed. 

Analytical methods to obtain pesticide concentrations for composited food samples have 
been developed with the goal of 1 ng/g detection limit. Specific detection limits for several 
pesticides in daily composited solid food samples are listed in Table 7-2 with the recoveries from 
medium fat composite diet samples (U.S. EPA, 2001). 

7.5 Exposure Factor Information 

Activities affecting dietary exposure are recorded in food diaries and supporting 
questionnaires. This information includes what foods were eaten, where the foods were eaten, 
and how much was eaten. Supporting questionnaires obtain other important information such as 
whether the diet was typical, activities that occurred that may influence exposure like recent 
application of pesticides, etc. The NERL Hygiene and Dietary Habit Survey and food diary are 
presented in Appendix B. 


60 


Table 7-2. Method Detection Limits and Pesticide Recoveries 3 from Medium Fat Composite 
Diet Samples Fortified at 1, 5 and 10 ng/g._ 



%Recovery 


Pesticide 

1 ng/g 

5 ng/g 

10 ng/g 

MDL b 

Trifluralin 

93 

104 

108 

0.4(1) 

Phorate 

80 

94 

113 

1.7(5) 

Hexachlorobenzene 

68 

82 

92 

0.4(1) 

Dicloran 

41 

86 

115 

1.7(5) 

Simazine 

56 

86 

85 

1.9 (5) 

Atrazine 

101 

100 

106 

2(5) 

Terbufos 

80 

96 

113 

0.3 (1) 

Fonofos 

99 

101 

105 

1.5 (5) 

Diazinon 

101 

102 

106 

1.4 (5) 

Chlorothalonil 

77 

75 

124 

0.5 (1) 

Acetochlor 

184 

95 

110 

1.4(5) 

Alachlor 

106 

88 

104 

0.4 (1) 

Aldrin 

108 

84 

99 

1(5) 

Malathion 

109 

106 

115 

1.7(5) 

Metolachlor 

78 

92 

105 

0.2(1) 

Chlorpyrifos 

97 

97 

102 

0.5(1) 

Parathion 

101 

119 

117 

1.8(5) 

Dacthal 

91 

94 

105 

0.3 (1) 

Isofenphos 

80 

99 

111 

0.4(1) 

g-Chlordane 

62 

81 

95 

0.2(1) 

Endosulfan-I 

96 

82 

96 

0.4(1) 

a-Chlordane 

69 

82 

97 

0.2(1) 

Dieldrin 

115 

92 

99 

0.4(1) 

DDE 

80 

94 

102 

0.2(1) 

Endrin 

0 

89 

73 

2.4(10) 

DDD 

111 

145 

183 

5.3 (10) 

cis-Permethrin 

175 

120 

105 

3.5 (10) 

trans-Permethrin 

175 

134 

102 

3.2 00) 


3 n = 7 for each concentration. 

b Method detection limits were calculated using either 1, 5 or 10 ng/g fortification levels as indicated in 
parentheses. Method detection limits are not reported for analytes with recoveries less than 60%. 
(Rosenblum et al., 2001) 


61 




































8.0 


APPROACH FOR ESTIMATING INDIRECT INGESTION EXPOSURE 


8.1 Introduction 

Ingestion exposure by indirect pathways has been identified as a potentially significant 
route of pesticide exposure for infants and young children (Cohen Hubal et ah, 2000). Indirect 
ingestion exposures occur when children place objects that have become contaminated with 
pesticides, including their hands, in their mouths. Pesticides are ingested as a result of transfer 
from the object, or, for foods, when they are consumed. 

In addition to the dietary ingestion exposures associated with the foods that children eat 
(Section 7.0), the manner in which children handle food as they eat may also impact their 
exposure to environmental contaminants. Small children are less likely than adults to consume 
food in a structured environment. Small children may sit on the floor or lawn to eat and often 
pick up and eat foods that have fallen on the floor. Infants and young children also eat most of 
their food with their hands. Increased exposure occurs when children handle and eat foods that 
have come in contact with the floor or other contaminated residential surfaces (Melnyk et al., 
2000; Akland et al., 2000) and hands. Indirect ingestion associated with foods consumed, 
together with dietary ingestion associated with contaminants inherent to foods, constitutes total 
ingestion from the dietary pathway. 

Children’s mouthing behaviors also contribute to the potential for indirect ingestion 
resulting from contact with contaminated objects and surfaces in the environment. Sucking and 
mouthing hands and objects are natural behaviors in childhood development. Infants are bom 
with a sucking reflex, providing them with both nutrition and a sense of comfort or security. If 
infants do not receive unrestricted breast feeding, they will suck on a pacifier, thumb (or other 
finger), or other object like a blanket or stuffed animal. As infants develop, they begin to explore 
their world through mouthing (Groot, 1998). During this stage of development, children put 
almost everything that they contact into their mouths for a few seconds. Young children may 
also begin to use the mouth as a third hand, placing some objects in the mouth in order to manage 
them. 


Teething is another important stimulus for mouthing activities. Biting and chewing on 
fingers and objects to relieve the discomfort of teething may be extensive. Teething usually 
begins between 4 and 7 months of age, but may start several months earlier or later. As with all 
childhood behaviors, mouthing activities vary significantly from child to child and, therefore, the 
impact on exposure will also be highly variable. 

8.2 Summary of Data Requirements 

Because it would be too burdensome and costly to collect all the data required to apply 
the microactivity approach as presented in Section 3.4, a macroactivity approach is presented 


62 


here to provide a simplified assessment of indirect ingestion exposure to an individual based on 
measurement data collected in the field. In this approach, objects (including hands and food) that 
are commonly handled, mouthed, and/or ingested are identified in the field. The residue loadings 
on these objects are measured directly or estimated from surface concentration measurements. 
General information relating to the frequency and nature of these mouthing and ingestion 
activities is also collected. Data on the fraction of residues that may be removed from an object 
during mouthing that has been obtained in the laboratory experiments is then required to 
complete the assessment. A summary of the data requirements for this approach is presented in 
Table 8-1. 


Table 8-1. Data Requirements for Estimating Indirect Ingestion Exposure 


Parameter 

Measurement 

How Collected 

Units 

Indirect Ingestion Exposure - Macroactivity Approach 

Emg/mi = (C X )(TE X )(SA X )(EF) 

X 

Hand, object, food item or 
anything else that enters the mouth 



c x 

Contaminant loading on x 

Wipes, washes or surface 
samplers, samples of handled 
food 

pg/cm 2 

TE X 

Transfer efficiency of contaminant 
from x to mouth 

Measured in the laboratory, 
estimated from the literature 

unitless 

SA X 

Area of x contacted by mouth 

Questionnaire 

cm 2 /event 

EF 

Frequency of indirect ingestion 
events over a 24-h period 

Questionnaire 

event/d 


8.3 General Considerations 

Ingestion exposure occurs by direct ingestion of foods containing pesticide residues. 
These residues are the result of agricultural use of pesticides and are in the food when the food is 
brought into the residential environment. Ingestion exposure may also occur by indirect 
ingestion of residues on objects, hands, and food that are placed in the mouth. These residues are 
transferred from surfaces and objects in the residential environment directly to hands, to food, or 
additionally from hands to food. Indirect ingestion exposures are difficult to quantity and assess 
because there are no methods for directly measuring contaminants that are ingested by these 


63 
















pathways. 


Instead, measurement of residues on hands, objects, and foods collected at specific time 
points are used to estimate ingestion exposures over the time frame of interest. Measurements of 
contaminant loading collected at a single point in time, however, may not reflect changes in 
loading which occur prior to, or subsequent to, sampling (e.g., evaporation or removal by hand 
washing or mouthing). Contaminant loading over time can vary significantly and is often the 
result of discrete events. Thus, current sampling techniques result in an integrated loading over 
extended time periods, and variations in time cannot be characterized. To facilitate interpretation 
of these data, measurements of residues on hands, objects, and handled foods need to be related 
to activities that occur in the same time interval. As much as is possible, exposure media 
concentrations need to be linked directly to contact activities. 

To conduct a more detailed analysis of the time course of exposure, as is the goal of an 
exposure model like SHEDS, very detailed time-sequence activity data are required. To collect 
this type of data, a diary survey structure designed to collect sequential location/activity data for 
each discrete behavior of interest or videotaping is required. The burden of such a diary survey 
precludes inclusion in the type of children’s exposure study covered by this protocol and should 
therefore be considered for a separate study. 

One additional consideration: in the time frame of concern for this scenario (short term 
following an application), exposure resulting from ingestion of soil and house dust is assumed to 
be less important than indirect ingestion of residues. If during the preliminary screening 
assessment, soil and dust ingestion pathways are identified as potentially important, these can be 
easily addressed by the addition of dust and soil samples to the required field measurements. 

8.4 Monitoring Methods 

To estimate the contaminant loading on the objects which a child may contact by indirect 
ingestion pathways, the following field samples are required: 

• Samples of residue loadings from any residential surfaces that are frequently mouthed 
(e.g., surface press on coffee table), 

• Samples of residue loadings from the surfaces of objects that are frequently mouthed 
(e.g., surface wipe on toy), 

• Samples of residue loadings from the child’s hands or other body parts that are frequently 
mouthed (e.g., hand wipe), 

• Samples of foods that have been handled in the child’s normal eating environment (e.g., 
cheese handled by child prior to eating), and 

• Samples of foods that have contacted surfaces during eating (e.g., cheese that has been 
placed on counter tops, floors, or high chair trays). 


64 


Information on the relevant surface sampling techniques has been included in Section 6 
on dermal exposure. Removal techniques used to measure residues on smaller objects, hands, 
and foods are discussed below. 

Surface Loading Measurements . Surface wipe, press, or rolling methods are used to 
estimate the total or potential amounts of pesticides available for transfer from surfaces such as 
floors, furniture, window sills, counters, and toys. There are several methods that have been 
developed, as described in Section 6.4, but all are similar in that a material, generally cotton 
gauze or some filter material, either wetted with a solvent (isopropanol, water, saliva simulant) or 
dry, is used to wipe, press, or roll on a specified surface area. Appropriate methods need to be 
selected based on the type of surface (e.g., wipes are applicable for hard surfaces, but not for 
carpet). The collection material is then extracted, and analyzed for pesticides by GC/MS, 
GC/ECD, or other suitable instrumental method. 

Hand Wipe or Rinse . Hand wipe and rinse methods are used to estimate the total or 
potential amounts of pesticides available for mouthing. Handwash sampling procedures can be 
standardized to ensure that they are operator-independent (Davies, 1980). Skin wiping 
procedures are inherently operator dependent. Removal sampling techniques are limited in that 
these measure only what can be removed from skin at the time of sampling rather than the actual 
skin loading. Findings suggest that data collected using removal techniques are difficult to 
interpret and require appropriate laboratory removal efficiency studies for use. However, 
because hand wipes are being used here to assess indirect ingestion exposure and not dermal 
exposure, the removal is likely more representative of what is available for indirect ingestion 
than for dermal absorption. As such the major limitation is that current sampling techniques do 
not reflect loadings or losses which occur subsequent to sampling. NERL is addressing issues 
related to hand wipe sampling and is developing and evaluating standardized procedures. 

Collection of Handled Food . Individual samples of foods that have been handled by the 
child can be collected to estimate the pesticide loading on the food items caused by contact with 
contaminated surfaces and hands. One approach used by NERL has been to identify food items 
that a child in the study was known to handle when eating. During the monitoring period, the 
caregiver for the child collects one set of the individual food items that were not touched by the 
child and a second set that were touched (handled) by the child. Analyses of the two sets of the 
individual food items provide the amount of pesticides transferred onto the foods. In other 
studies, samples of foods have been contacted with surfaces by the monitoring technician to 
directly measure the potential for transfer. 

Soil and Dust Sampling . Although not included as part of this scenario, soil and dust 
samples may be collected if it is determined that those pathways are potentially important for 
indirect ingestion. 


65 






Selection of Objects for Sampling . The objects to be sampled should be: 


• representative of the objects that the child frequently comes in contact with and 

• amenable to the designated methods of sampling. 

Information pertaining to these two points is generally obtained through discussions with the 
child’s caregiver and/or by observation of the child’s activities. Questionnaires can also be 
developed to provide a systematic approach to defining the objects appropriate for sampling. All 
samples should be collected such that the measurements can be related in time to the activity data 
in the questionnaires. 

Sampling Considerations . Many of the sampling considerations for the indirect ingestion 
route of exposure are similar to those presented for the dermal route. However, there are several 
considerations specific to this route and the residue removal and food samples that must be 
collected. Outlined below are the additional issues that should be considered when designing 
and collecting samples associated with the indirect ingestion route in a measurement-based 
assessment. 

• Physical surface characteristics, contaminant surface loading, sampling material, and 
wipe sampling procedures all influence accuracy and precision of measurements. (Fenske, 
1993) 

• Area dimensions of objects to be monitored should be based on a practical limit of 
detection (LOD) for the analytical method that will be used. Samples being analyzed by a 
laboratory method that is very sensitive (low LODs) will require a smaller sampled area 
than samples being analyzed by a method that is less sensitive (high LODs). Detection 
limits should be sufficiently low to insure that not detected values represent 
concentrations considered insignificant as defined by the study goals. 

• Practical limits of detection should also be considered in choosing the solvent for the 
removal techniques. While a saliva simulant is likely to give a sample that is more 
representative of a transferable residue, isopropanol may provide a sample that is easier to 
analyze. Requirements for method detection limits and performance were discussed in 
Section 6.4. 

• Hand wipe and hand wash techniques assess contamination adhering to an individual’s 
skin at the time of sample collection. Measurements of skin loading do not reflect losses 
which occur subsequent to sampling; e.g. evaporation or removal by hand washing. Skin 
loading over time may vary significantly and may be the result of many discrete events. 
Current sampling integrates dermal loading over extended time periods. Therefore, 
variations in time cannot be characterized. 

• Food items should be collected that are of sufficient quantity such that there will be 
leftovers for collection, both handled and not handled. Alternatively, use standardized 
food items that can be contacted with contaminated surfaces so that sources of 
contamination can be identified, both within and among exposure scenarios. 


66 




8.5 Exposure Factor Information 

To estimate indirect ingestion exposure, information must be collected to describe the (1) 
characteristics of the child, (2) activity information associated with mouthing and ingestion of 
objects by the child, and (3) information on the transfer of residues from the objects to the mouth. 

Characteristics of Child . The minimum information required to characterize the child is 
the child’s age, weight, gender, and hand surface area. These variables are used to estimate 
ingestion rates and may be used to estimate mouthing and related behavior. 

Activity information . An activity questionnaire is used to collect information on: (1) the 
objects that are mouthed or eaten most often by a child and (2) the characteristics of the activities 
that potentially result in indirect ingestion of the contaminant of interest. By collecting 
information on the important objects, field sampling can be directed to collect residue loading 
samples from these items. Information on mouthing characteristics (e.g., frequency, surface area 
mouthed), hand washing practices, eating environment, and the likelihood of the child handling 
food items should be linked to the sampled items to facilitate assessment of indirect ingestion 
exposure. Examples of the information to be collected and the types of questions required to 
collect the relevant activity information are presented in Figures 8-1 and 8-2. Figure 8-2 presents 
examples of questions from the NERL Hygiene and Dietary Habit Survey, a copy of which is 
included in its entirety in Appendix B of this document. 

Obiect-to-Mouth Transfer Efficiencies . Object-to-mouth transfer efficiency may be a 
function of object surface characteristics (e.g., plush vs hard), and mouthing mechanics (e.g., 
sucking vs licking). The need to develop residue transfer data for mouthing activities was 
identified in the NERL Dermal and Non-dietary Exposure Workshop conducted in 1999. 
Laboratory studies are being conducted by NERL using a surrogate mouthing method to identify 
the important parameters for characterizing these transfer efficiencies and to develop a set of 
transfer efficiency data. 

Soil and dust ingestion rates . Indirect ingestion of soil and dust has been monitored in 
fecal samples using tracer elements (Binder et al., 1986; Calabrese et al., 1989; Van Wijnen et 
al., 1990; Davis et al, 1990; Calabrese et al., 1997). These studies require collection of dietary 
data and concentrations of contaminants in residential soil and dust to link the tracers to ingested 
soil and then to estimate ingestion of contaminants. Results of the limited monitoring conducted 
using this technique are currently used to provide bounding estimates for soil ingestion which 
can then be combined with information on the concentration of pesticides in dust and soil to 
estimated indirect ingestion exposure by this pathway. 


67 






Figure 8-1. Examples of data required for assessing indirect ingestion exposure and sample 
questions. 

HOME QUESTIONNAIRE 

1. Hand surface area 

2. Is your child currently teething? 

3. Does your child, put toys or other objects in his/her mouth? 

1. Frequently (greater than 10 time/hour) 

2. Sometimes (2 to 10 times/hour) 

3. Almost Never (less than 2 times/hour) 


4. Please list the objects your child puts in his/her mouth most free 

uently 

Object 

Portion put in mouth 

Number of times/day 

Where handled 

1 . 




2. 




3. 




4. 




5. 





5. Does you child lick or mouth surfaces? 

1. Frequently (greater than 10 time/hour) 

2. Sometimes (2 to 10 times/hour) 

3. Almost Never (less than 2 times/hour) 

6. What surfaces does you child lick or mouth most frequently? Please list surface and 
location 

a. 

b. 

c. 


68 
















7. How frequently does you child put his/her hands in his/her mouth? 



During active play? 

During quiet play? 

Frequently (greater than 20 time/hour) 



Sometimes (5 to 15 times/hour) 



Occasionally (2 to 5 times/hour) 



Almost Never (less than 2 times/hour) 




8. How much of your child’s hand does s/he put into his/her mouth? 

a. thumb 

b. 2 fingers 

c. 4 fingers 

d. whole hand 

9. Does your child suck on his/her fingers when they are in the mouth? 

10. Does you child put, his/her toes or feet in his/her mouth? 

a. Frequently (greater than 10 time/hour) 

b. Sometimes (2 to 10 times/hour) 

c. Almost Never (less than 2 times/hour) 

DAYCARE QUESTIONNAIRE (Ask for each participating child:) 

1. Does s/he child, put toys or other objects in his/her mouth? 

1. Frequently (greater than 10 time/hour) 

2. Sometimes (2 to 10 times/hour) 

3. Almost Never (less than 2 times/hour) 

2. How frequently does s/he put his/her hands in his/her mouth? 

1. Frequently (greater than 20 times/hour) 

2. Sometimes (5 to 15 times/hour) 

3. Occasionally (2 to 5 times/hour) 

4. Almost never (less than 2 times/hour) 

3. Please lists the 5 toys or objects that children put in their mouths most frequently and 
where they are handled. 

4. How are toys washed and recycled? 


69 











Figure 8-2. Examples of questions included in the NERL Hygiene and Dietary Habit Survey 
(included in Appendix B). 

1. Does your child eat food with his/her fingers? What types? 

1. Yes 1. Often _ 

2. No 2. Sometimes _ 

9. Unknown 3. Almost never _ 

9. Unknown _ 


Where does your child usually eat his/her meals when at home? 

1. Kitchen 1. At table 

2. Living room 2. High chair 

3. Bedroom 3. Chair or couch 

4. Dining room 4. Sitting on the floor 

5. Other_ 5. Other_ 

9. Unknown 9. Unknown 


3. Where does your child usually eat his/her snacks? 

1. Kitchen 1. At table 

2. Living room 2. High chair 

3. Bedroom 3. Chair or couch 

4. Dining room 4. Sitting on the floor 

5. Other_ 5. Other_ 

9. Unknown 9. Unknown 


4. What snacks does your child usually eat at home? 

1 . _ 

2 . _ 

3. _ 

4. _ 

5. _ 

5. How frequently does your child eat food off of the floor? 

1. Often 2. Sometimes 3. Almost never 

9. Unknown 


70 

















6 . 


Does your child ever prepare or get his/her own food? 

(for instance peel a banana, get a bowl of cereal, finger foods) 

What foods? 

1. Yes 1. Often _ 

2. No 2. Sometimes _ 

9. Unknown 3. Almost never _ 

9. Unknown _ 


7. Does an older brother or sister ever prepare or get your child’s food? 

(For instance peel a banana, get a bowl of cereal, finger foods) 

What foods? 

1. Yes 1. Often _ 

2. No 2. Sometimes _ 

9. Not applicable 3. Almost never _ 

9. Unknown _ 


8. Does your child ever eat food after it has dropped on the floor? 

What foods? 

1. Yes 1. Often _ 

2. No 2. Sometimes _ 

9. Not applicable 3. Almost never _ 

9. Unknown _ 


9. Does your child drink from bottles? 


1. Yes 

2. No 

9. Not applicable 


1. Often 

2. Sometimes 

3. Almost never 
9. Unknown 


71 





















9.0 OTHER DATA COLLECTION 

9.1. Questionnaire Data To Identify Sources and Usage of Pesticides in Residences and 

Daycares 

9.1.1 Introduction 

The previous sections of this document have described the data requirements and 
approaches for estimating children’s aggregate exposure to pesticides. For the measurement 
based approach described in the previous sections, time-activity diaries and questionnaires are 
used to collect data on the exposure factors that are needed to estimate exposure by the different 
routes and pathways. Well-designed questionnaires are also important to characterize sources, 
transport processes, and parameters that may affect spatial and temporal distribution of pesticides 
and environmental contaminants in human exposure studies. Information collected with 
questionnaires during exposure measurement field studies can aid in the interpretation of the data 
collected in measurement assessments and provide data for use in modeling assessments. 

Exposures to pesticides and environmental contaminants may result from many different 
sources and in many different microenvironments. Pesticide sources may include, but are not 
limited, to applications for the control of agricultural pests, outdoor turf and landscape pests, 
termite control, indoor pest control, and control of pests on pets. Pesticides may move or 
translocate from their source and point of application. They move from one location to another 
following several pathways. Pesticide applications may generate particles that drift from their 
original source. In addition, depending on the physical nature of the pesticide active ingredient 
and the formulation, vapors and/or pollutants sorbed to particles may result in pesticides or 
contaminants moving from the source to deposit at other locations. Finally, the physical uptake 
of residues and particles on an individual’s hands, feet, or clothing or by adhesion on the fur of 
pets such as cats and dogs may result in the physical translocation of contaminants or pesticides. 
Pesticides and environmental contaminants in the air may also infiltrate into the homes, daycares, 
schools and other buildings from the outdoors. 

9.1.2 Administering Questionnaires 

Site surveys and questionnaires are common methods to screen and characterize sources, 
and aid in identifying transport mechanisms and exposure pathways. Furthermore, they can be 
useful to gather general information regarding the study participants and their lifestyles and 
activities, the home or facility under study, and other parameters that may affect exposure or the 
interpretation of exposure measurement results. 

Prior to the initiation of the study, the research team should concisely define the type of 
information required to fulfill their research needs and evaluate the design to insure that while 
effectively capturing the desired information an excessive burden is not placed on the study 


72 


participants. 

Surveys may be completed by field scientists or adult study participants. The survey team 
should be available to address questions the participant may have regarding the survey. When 
administering survey questionnaires that collect information on pesticide use, it is especially 
important to have knowledgeable field team members who can provide assistance to study 
participants to complete the questionnaires. Assistance may be particularly important when 
querying the participants regarding specific products and pesticide applications because many 
occupants of homes have little familiarity with specific terms, chemical classes, or product 
groupings. To overcome some of the problems of obtaining accurate information about pesticide 
use in residences, the field team may request to view areas where cleaners, pesticides and other 
household products are stored in order to collect chemical names and registration numbers for 
future identification. The problem of collecting accurate usage information may be even greater 
when attempting to collect information in daycares or schools where pesticides are applied by 
commercial applicators. In these environments, it is generally necessary to work with building 
management and facility managers to obtain service and application records. 

Following completion of questionnaires, a member of the survey team should review the 
forms to insure completeness and legibility. Similarly, forms completed by the field team should 
undergo a quality assurance check by the team lead to determine completeness, accuracy and 
legibility. 

9.1.3. Information on Sources to be Collected in Pesticide Exposure Measurement Studies 

To obtain accurate information on pesticide sources and usage in residences, a simple 
questionnaire should be designed that collects information on what pesticides were used, when 
they were applied, where applied, and how applied. Figure 9-1 presents examples of questions 
that can be used to collect this information. The example questions would be used to address the 
specific scenario described in Section 4 for short-term exposure during a period of one to seven 
days following application. The sample questions are not all inclusive. Additional questions will 
be required to address different exposure scenarios. A different set of questions would be 
required to assess long-term exposure to pesticides. Additional questions would also be required 
for population modeling-based approaches for exposure assessment. Researchers in NERL are 
currently developing a questionnaire that will be used with this protocol. 

In addition to the questions that specifically address recent pesticide applications in the 
home, questions should be included to determine other potential sources of pesticides in the 
home. Pesticide residues may be physically transported on the clothing, shoes and the body of 
individuals from their workplace to home. Questions to determine occupational exposure as a 
source might include those in Figure 9-2. 


73 


Figure 9-1. Example questions use to collect information on pesticide usage in a residence. 


1. Did anyone apply pesticides within your home, in your garden or in your yard within the 
past 2 weeks? 

_Yes. (If yes, go to l.b. through l.h) 

_No 

_Don’t Know 

1 .b. Where and when was it applied? 

_in the home (if checked, screen gives detailed list of choices for kitchen, 

pantry, living room, bathrooms, bedrooms, under sinks, floors, at 
baseboards, cupboards, window sills, at a specific site of infestation, etc.) 

_in the basement 

_in the garage 

_in storage areas 

_outside along the walls 

_under the crawl space 

_in the yard 

_in the garden 

_on the pet (s) 

_on a deck or wood surface 

_on cement or patio surface 

_Don’t know 


(next screen gives choices of when applied) 

_today _within 24-48 hours_3-5 days_1 week_2 weeks_last month 

1 .c. For indoor applications, how was it applied? 

_crack and crevice spray (liquid) along walls 

_sprayed (liquid) in the room 

_fogger (aerosol in a can) 

_dust 

_bait in a container 

_bait not in a container 

_applied to pet as a liquid or shampoo 

_applied to pet as a powder 


74 

















1 .d. For non-indoor living area applications, including crawl space, how was it 
applied? 

_foundation spray (liquid) along walls 

_dust or pellets on yard, garden or lawn 

_spray on yard, garden or lawn 

_bait in a container 

_bait not in a container 

_applied to pet as a liquid, shampoo, or powder 

_don’t know 

1 .e Who applied the pesticide? 

_applied by yourself 

_applied by another adult in the home 

_applied by a commercial applicator 

don’t know 


1 .f. For what purpose was the pesticide applied? 

_ants _mosquitos _fungi/molds/bacteria _weed control 

_roaches _other flying insects _plant disease _other purpose 

_fleas termites other insects don’t know 


1 .g. Did you have to mix the chemical with water before applying? 

_yes _no 

1 .h. Give the name and EPA number (if known) of the products that were applied 

during the past 2 weeks. The EPA registration number is located on the label of 
the product. (Photo to show example) 


Pesticide #1: 
Pesticide #2: 
Pesticide #3: 
Pesticide #4: 
Pesticide #5: 


EPA Reg. No: 
EPA Reg. No: 
EPA Reg. No: 
EPA Reg. No: 
EPA Reg. No: 


75 





























Figure 9-2. Questions on occupational exposure to pesticides. 

2. Does anyone in the home work in a manufacturing job that involves handling of 
pesticides or who works in a facility where pesticides are produced or handled? 
Yes No 


2a. If yes, what pesticides? 

Pesticide #1:_ 

Pesticide #2:_ 

Pesticide #3:_ 

2b. If yes, are his/her clothes and shoes changed before leaving the facility? 
Yes No 


3. Does anyone in the home work in on a farm or in an agricultural job that involves 
handling of pesticides or crops treated with pesticides? _Yes _No 

3 a. If yes, what pesticides? 

Pesticide #1:_ 

Pesticide #2:_ 

Pesticide #3: _ 

Pesticide #4:_ 

Pesticide #5: _ 

3b. If yes, are his/her clothes and shoes changed before entering your home? 

Yes No 


76 




















Additional questions with greater detail may be added for field studies involving 
measurements of pesticide by children of agricultural farm worker’s families. These questions 
may include identification of local sources of agricultural pest control applications, proximity to 
residences and daycares, direction from these sources, and questions related to potential spray 
drift. 


9.1.4 Information on Microenvironment Surfaces, the Structure and the Occupants 

In order to obtain accurate estimates of dermal exposure, it is important to collect 
information on the surfaces that the child contacts in the residence or daycare. This information 
will be used to determine the appropriate transfer coefficients and efficiencies to develop in 
laboratory and field experiments and to use in the algorithms for estimating dermal and indirect 
ingestion exposure. During field data collection, the type of flooring material should be 
identified in each room where the child spends time. This may include hard surfaces such as 
vinyl flooring, ceramic flooring, wood, and other materials. Carpet type (short nap, plush, etc.) 
should also be recorded. This information should be recorded for all rooms that are occupied by 
the child. Development of the questions to collect this information is on-going in NERL. 

For most field exposure measurement studies, the information on the structure can be 
limited to a simple diagram of the residence showing the locations of rooms in the structure and 
the sampling locations. Detailed information on the construction materials, size, age, heating and 
cooling systems, etc. are not required for the purpose of estimating exposure, although they may 
be useful for understanding the measurement data. Similarly, detailed information on occupant 
activities beyond that collected with the time-activity diaries described in the previous sections is 
generally not required, but it may be useful for interpreting the measurement data. 

The type of information to be collected on the structure and the occupant activities will be 
determined by the study objectives. Superfluous information should not be collected as it 
increases participant burden and resources for performing the field studies. If the study data 
analysis plan does not include a purpose for collection of information about the structure or the 
occupants, it should not be collected. 

9.1.5 Additional Data Collection for SHEDS-Pesticide Model 

Additional data are needed for the SHEDS-Pesticides model (described in Appendix A) 
that are not required in exposure assessments that use the individual measurement-based 
approach for which this protocol was developed. Some of those additional requirements for 
pesticide usage include the following: 


1 . 

2 . 

3. 


Number of Applications 

Month First Applied 

Time Interval Between Applications 


77 


4. Day of Week Used 

5. Reentry Interval 

6. Scenario-Specific Area (e.g., Lawn, Garden, House) 

7. Scenario-Specific Area with a Chemical 

8. Scenario-Specific Area with the Chemical of Interest 

9. Scenario-Specific Area with the Chemical of Interest via the Formulation 

10. Scenario-Specific Area with the Chemical of Interest via the Formulation and Application 

Method 

11. Residences Treating Entire (vs. Spot Treatment of) Scenario-Specific Area with the 
Chemical of Interest via the Formulation and Application Method 

12. Number of Applications Treating Entire (or Spot Treated) Scenario-Specific Area with 
the Chemical of Interest via the Formulation and Application Method 

13. Area Treated for Total Area Application 

14. Fraction of Total Area for Spot Treatment 

15. Application Rate 


78 


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U.S. EPA. (1999b). Compendium of Methods for the Determination of Toxic Organic 
Compounds in Ambient Air - Second Edition, EPA/625/R-96/010b, Center for Environmental 
Research Information, http://www.epa.gov/ttn/amtic/airtox.html 

U.S. EPA (2000a). Strategy for Research on Environmental Risks to Children. Office of 
Research and Development, Washington, D.C. EPA/600/R-00/068, August, 2000. 
http://www.epa.gov/ncea/risk2kids.htm 

U.S. EPA (2000b). Summary Report of the Technical Workshop on Issues Associated with 
Considering Developmental Changes in Behavior and Anatomy when Assessing Exposure to 
Children. EPA/630/R-00/005, U.S. Environmental Protection Agency, Washington DC. 
http://www.epa.gov/ncea/raf/wrkshops.htm 

U.S. EPA (2000c). Child-Specific Exposure Factors Handbook. NCEA-W-0853 June 2000 
External Review Draft, U.S. Environmental Protection Agency, Washington DC. 
http://www.epa.gov/ncea/csefh2.htm 

U.S. EPA (2001) Manual of Analytical Methods for Determination of Selected Environmental 
Contaminants in Composite Food Samples. EPA report (in preparation). 

Vaccaro,J. R., and R. J. Cranston (1990). “Evaluation of dislodgeable residues and absorbed 
doses of chlorpyrifos following indoor broadcast applications of chlorpyrifos-based emulsifiable 
concentrate.” Dow Chemical Company, Midland, MI. 

Van Wijnen, P. Clausing, B. Brunekreff (1990). “Estimating soil ingestion by children.” 

Environ. Res. 51:147-162. 


83 








Whitmore, R. W., F. W. Immerman, D. E. Camann, A. E. Bond, R. G. Lewis, and J. L. Schaum. 
(1994). “Non-occupational exposures to pesticides for residents of two U.S. cities.” Arch. 
Environ. Contam. Toxicol. 26: 47-59. 

Wright,C. G., R. B. Leidy, and H. E. Dupree (1993). “Cypermethrin in the ambient air and on 
surfaces in rooms treated for cockroaches.” Bull. Environ. Contam. Toxicol. 51:356-360. 

Zartarian V. G., H. Ozkaynak, J. M. Burke, M. J. Zufall, M. L. Rigas, and E. J. Furtaw Jr. (2000). 
“A modeling framework for estimating children's residential exposure and dose to chlorpyrifos 
via dermal residue contact and non-dietary ingestion,” Environ. Health Perspect., 108(6):505- 
514. 


84 


APPENDIX A 


Description of the ORD/NERL Stochastic Human Exposure and Dose 
Simulation Model for Pesticides (SHEDS-Pesticides) 











































































The Stochastic Human Exposure and Dose Simulation model for pesticides (SHEDS- 
Pesticides) developed by ORD/NERL is a probabilistic, physically-based model that simulates 
aggregate exposures for population cohorts and multi-media pollutants of interest. SHEDS 
simulates individuals from the user-specified population cohort by selecting daily sequential 
time/location/activity diaries from surveys contained in EPA’s Consolidated Human Activity 
Database (e.g., the National Human Activity Pattern Survey). Depending on the type of pesticide 
usage information entered, SHEDS can be used to simulate one day post-application exposures 
from a single application event or daily, weekly, monthly, seasonal, or annual average exposures 
from repeated pesticide applications over a year. It can also yield results for user residences only 
or for the entire population of both user and non-user residences. 

Exposure time profiles are the basis of the SHEDS exposure calculations. These are plots 
of instantaneous exposure (mass, concentration, or mass loading at the external human boundary) 
against time that preserve within-day peaks and variability as an individual moves throughout his 
or her day. These exposure profiles can yield toxicologically relevant dose profiles, and 
ultimately, improved risk estimates. They are constructed separately for each of the four 
exposure routes included in SHEDS — inhalation, dietary ingestion, dermal contact, and non¬ 
dietary ingestion (from hand-to-mouth and object-to-mouth pathways)- and the time step is the 
duration of the CHAD diary location-activity combinations. To generate a daily inhalation 
exposure profile, SHEDS samples from indoor or outdoor air concentration distributions 
corresponding to locations occupied by the sampled individual’s diary. The air concentrations 
are then combined with sampled values from activity-specific energy expenditure distributions 
and basal metabolic rates for the diary-reported activities. Dermal exposure is modeled by 
combining dermal transfer coefficient information with surface residues and time spent at and 
near the applied surfaces. For bathing related locations and activities, a washing removal 
efficiency is applied to the profile to simulate the reduced dermal loading. Non-dietary ingestion 
exposure from hand-to-mouth and object-to-mouth transfer is simulated by combining dermal 
hand loading or object residues with fraction of hands or objects inserted into the mouth, 
frequency of mouthing activities, and saliva removal efficiency. Non-dietary ingestion via hand- 
to-mouth contact is subtracted from the dermal exposure profiles. The dietary module in SHEDS 
uses the latest USDA/EPA recipe files and 1994-1996, 1998 Continuing Survey of Food Intakes 
by Individuals (CSFII) consumption data, which includes about 10,000 food types and 21,660 
person-days. CHAD individuals are matched with CSFII individuals, and for each CSFII person, 
the reported consumption data are combined with sampled residue values in foods as eaten to 
yield a modeled mass of residue ingested by meal. To obtain residue values in foods as eaten, 
SHEDS applies the recipe files to the CSFII food types to break the food into raw agricultural 
commodities (RACs), and then combines the RAC residues with use and processing factors. 

To simulate one day post-application exposures for a population cohort, SHEDS samples 
a single diary and combines the sequential location-activity durations with sampled values from 
user-specified probability distributions for environmental media concentrations (either calculated 
from user-specified application rates or sampled from user-specified distributions of measured 


A1 


values) and exposure factors (e.g., saliva and washing removal efficiency, skin surface area 
contacted, surface area of objects mouthed) into route-specific algorithms described above to 
construct daily exposure time profiles. These exposure profiles can be combined with 
pharmacokinetic models to yield route-specific dose profiles that can then be aggregated. 

To simulate exposures from repeated applications over a year, SHEDS-Pesticides 
simulates, for each individual in an age-gender cohort, 365 days by sampling 8 CHAD diaries 
representing 1 person from each of 4 seasons and 1 person from each of 2 day categories 
(weekend and weekday); fixing 5 weekday dairies and 2 weekend diaries; and then repeating the 
7 day activity patterns within each season. It then sets days and times of pesticide applications 
over the year based on user-specified probabilities for pesticide usage. Based on these 
application times, environmental media residues and concentrations, either calculated from 
application rates or sampled from user-specified distributions of measured values, are set every 
day of the year for that individual. SHEDS then combines activities and residues with sampled 
values from probability distributions for exposure factors to generate longitudinal 1-year 
exposure profiles that can be entered as inputs to pharmacokinetic models to simulate the 
corresponding route-specific dose profiles. Once the dose profiles are obtained, they can be 
summed across routes to yield an individual’s aggregate dose profile for the chemical of interest. 

Once the exposure and dose profiles are generated for each individual, the metrics of 
interest (e.g., peak, time-averaged, time-integrated) are extracted from the individual’s profiles, 
and the process is repeated thousands of times to obtain population distributions. This approach 
allows identification of the relative importance of routes, pathways, and model inputs. Sensitivity 
analyses are conducted using stepwise regression and correlation methods to identify the relative 
importance of routes and model inputs. If the user enters uncertainty distributions associated 
with model inputs, SHEDS applies two-stage Monte-Carlo simulation to derive estimates of 
inter-individual variability in the population and uncertainty in estimated empirical exposure and 
dose distributions. 


A2 


APPENDIX B 


Examples of a Food Diary and a Hygiene and Dietary Habit Survey 

Used in Recent NERL Pilot Studies 











































































































HOW TO COLLECT FOODS AND BEVERAGES 


WHERE WE WANT YOU TO COLLECT FOOD 

1) Please collect only foods and beverages that are eaten at home, or are prepared at home 
but are eaten elsewhere. 

WHAT WE WANT YOU TO COLLECT 

1) Please prepare and collect a second portion (as close as possible to the exact amount) of 
every food or beverage your child eats at every meal, snack, or any other time on the 
collection days. 

2) This does not include vitamins, medicines, chewing gum, toothpaste, or any other non¬ 
edible item. 

3) Please collect a sample of any foods that your child has dropped on the floor. You should 
collect only those foods from the floor that your child is likely to eat after they have 
dropped on the floor. 

4) Please have your child eat the same foods he/she would have eaten if we were not here. 

WHEN WE WANT YOU TO COLLECT THE FOOD 

1) Please collect the foods and beverages eaten from midnight to midnight on_ 

HOW TO COLLECT THE DUPLICATE-DIET SAMPLE 

1) At every meal or snack, prepare a second plate with the same type and amounts of food 
you have prepared for your child. Include all spices, sauces, butter, salt, ketchup, etc. 
Prepare a second cup, glass, or other container with the same amount of beverage that the 
child will drink. If you can, please use the same kind of plates, cups, and glasses for the 
food collection as used for the meal. 

2) If you give your child more servings of food or beverage during the meal, add the same 
amount to the second plate, cup, or glass. Use more plates, cups, or glasses if necessary. 

3) At the end of the child’s meal, remove from the second plate, cup or glass the same 
amount of food as was left on your child’s plate, glass or cup. If you are able, remove any 
inedible portions, like bones or pits, from foods on the second plate. The food or 
beverage that is now on the second plate or in the second cup should be the same amount 
that your child ate or drank. 

5) We have given you four zip-lock bags: one marked breakfast, one marked lunch, one 
marked dinner, and one marked snacks. Transfer the food on the second plate (not your 


B1 








child’s plate) to a zip-lock bag for the meal that was just eaten. Seal the bag. Place the 
bag in your refrigerator if it contains foods that could spoil. 

6) Add all beverages from the second cup (not your child’s cup) to the plastic bottle. Frozen 
items that could melt, like ice cream or popsicles, should also be put into the plastic bottle 
with the beverage samples not with the food samples. 

7) Close the jar lid and put the jar in your refrigerator. 

HOW TO USE THE 24-HOUR FOOD DIARY 


INSTRUCTIONS 

(1) We want you to list all of the foods, beverages, or drinking water that your child 
eats or drinks from midnight to midnight. 

(2) Every time your child eats, write down the name of the meal (breakfast, lunch, 
dinner, snack). 

(3) Then write down on a separate line the name of every food or beverage that your 
child eats or drinks. 

(4) For food mixtures such as stews or potpies, please write down the major kinds of 
foods in the mixture. Use the lines immediately below the one on which the name 
of the mixture is entered. 

(5) For beverages (including water), write down how many cups or glasses that your 
child drink(s). 

(6) When we collect the food samples, we will ask you several questions about each 
food that your child ate. These will include: 

(a) In the last month, how often did your child eat this food each week? 

(b) Where was the food that you collected eaten? 

(c) Did any of the food eaten have contact with your child’s hands, the floor, or 
other surfaces? 

(d) Were foods cooked in or prepared with tap water? 

(e) Were beverages cooked in or prepared with tap water? 


B2 





B3 






























FOOD DIARY - SUPPLEMENTARY QUESTIONS 


COMPLETE ON SAME DAYS FOOD IS 
RECORDED IN DIARY AND SAMPLES 
COLLECTED 


DAY: 1 

DATE: / / 


2 

/ / 


3 

/ / 


1. Please think back, were there any foods or beverages that 
you could not or did not collect for use: (LIST 


IDENTITY, SOURCE, AND AMOUNT OF EACH 
MISSING FOOD AND THE DAY IT WAS NOT 
COLLECTED.) 


YN 


YN 


YN 


a. At Breakfast 


b. At Lunch 


YN 


YN 


YN 


YN 


YN 


YN 


c. At Dinner 


YN 


YN 


YN 


d. For Snacks 


B4 





























COMPLETE ON SAME DAYS FOOD IS DAY: 

RECORDED IN DIARY AND SAMPLES DATE: 

COLLECTED 

1 

/ / 

2 

/ / 

3 

/ / 

2a. Did (your child), for any reason, eat more or less food 




than usual? (READ CHOICES AND ENTER a OR b). 




a. More food than usual -4 GO TO 2b. 




b. Less food than usual -4 GO TO 2b. 




c. Same as usual -4 GO TO 3. 




2b. Because of: (READ CHOICES AND CIRCLE ALL 




THAT APPLY.) 




a. Travel or vacation . 

a 

a 

a 

b. Weight control diet. 

b 

b 

b 

c. Illness or medical condition . 

c 

c 

c 

d. Work or school schedule. 

d 

d 

d 

e. Entertainment or social occasion . 

e 

e 

e 

f. Because of the food collection study . 

f 

f 

f 

g. Other (Specify day): 

g 

g 

g 





3a. Did (your child), for any reason, eat different foods than 




(your/his/her) usual diet? (CIRCLE Y FOR YES AND N 




FOR NO.). 

YN 

YN 

YN 

3b. If yes, was that because: (READ CHOICES AND 




CIRCLE ALL THAT APPLY.) 




a. Travel or vacation . 

a 

a 

a 

b. Weight control diet. 

b 

b 

b 

c. Illness or medical condition . 

c 

c 

c 

d. Work or school schedule. 

d 

d 

d 

e. Entertainment or social occasion . 

e 

e 

e 

f. Because of the food collection study . 

f 

f 

f 

g. Other ISpecifv dav): 

g 

g 

g 






B5 






























COMPLETE ON SAME DAYS FOOD IS DAY: 

RECORDED IN DIARY AND SAMPLES DATE: 

COLLECTED 

1 

/ / 

2 

/ / 

3 

/ / 

4a. List all of the floor foods collected. 

4b. Where were floor foods collected from? 





B6 







Hygiene and Dietary Habit Survey 


Parent’s name: _ Child’s name: _ 

How old is your child? _ DOB: _ 

How much does your child weigh (use a scale ?) _ 

We want to ask some questions about_(name of 

child). We are interested in the foods your child eats, and how the food is stored and prepared. 
We want to find out if these things influence your child’s lead exposure. 

Part 1. We now have some questions about vour child’s eating habits. 

1. Does your child eat food with his/her fingers? What types? 

1. Yes 1. Often _ 

2. No 2. Sometimes _ 

9. Unknown 3. Almost never _ 

9. Unknown _ 


2. Where does your child usually eat his/her meals when at home? 


1. Kitchen 

2. Living room 

3. Bedroom 

4. Dining room 

5. Other_ 

9. Unknown 


1. At table 

2. High chair 

3. Chair or couch 

4. Sitting on the floor 

5. Other_ 

9. Unknown 


3. Where does your child usually eat his/her snacks? 


1. Kitchen 

2. Living room 

3. Bedroom 

4. Dining room 

5. Other_ 

9. Unknown 


1. At table 

2. High chair 

3. Chair or couch 

4. Sitting on the floor 

5. Other_ 

9. Unknown 


B7 

















4. What snacks does your child usually eat at home? 


1 . _ 

2 . _ 

3 . _ 

4. _ 

5. _ 

5. How frequently does your child eat food off of the floor? 

1. Often 2. Sometimes 3. Almost never 

9. Unknown 

6. Does your child ever prepare or get his/her own food? 

(for instance peel a banana, get a bowl of cereal, finger foods) 

What foods? 

1. Yes 1. Often _ 

2. No 2. Sometimes _ 

9. Unknown 3. Almost never _ 

9. Unknown _ 


7. Does an older brother or sister ever prepare or get your child’s food? 
(For instance peel a banana, get a bowl of cereal, finger foods) 


1. Yes 

2. No 

9. Not applicable 


What foods? 

1. Often _ 

2. Sometimes _ 

3. Almost never _ 

9. Unknown _ 


8 . 


Does your child ever eat food after it has dropped on the floor? 

What foods? 


1. Yes 

2. No 

9. Not applicable 


1. Often 

2. Sometimes 

3. Almost never 
9. Unknown 


B8 






















9. Does your child drink from bottles? 


1. Yes 

2. No 

9. Not applicable 


1. Often 

2. Sometimes 

3. Almost never 
9. Unknown 


10. Do you have a cat in the home? 


1. Yes a. Does your child play with it before meals? 

2. No 


b. Does your child play with it during meals? 


11. Do you have a dog in the home? 


1. Yes 

2. No 

9. Unknown 

1. Yes 

2. No 

9. Unknown 


1. Yes a. Does your child play with it before meals? 

2. No 


b. Does your child play with it during meals? 


1. Yes 

2. No 

9. Unknown 

1. Yes 

2. No 

9. Unknown 


12. Has your child eaten outside in the past 3 months? 


1. Yes 

2. No 

9. Unknown 


how often? 

1. >3 times/week 

2. about l/week(go to 13) 

3. <1 /week (go to 13) 


where? (all that apply) 

1. backyard at home 

2. yard at friend’s or neighbors 

3. playground or park 

4. vacant lot or field 

5. alley 

6. street 

7. other places_ 


b. If yes, what sort of eating surface 


type of ground 


1. table 

2. bench or chair 

3. steps 

4. on the ground 

5. sandbox 


1. grass 

2. concrete or asphalt 

3. dirt or soil 

4. sandbox 

5. other_ 


B9 








9. unknown 


6. stroller 

7. other_ 

9. unknown 

13. a. How many times does your child wash his/her hands each day? 
b. When does your child wash his/her hands? (check all that apply) 

1. before meals 

2. after meals 

3. before snacks 

4. after snacks 

5. after going to the bathroom 

6. before going to bed 

7. after coming in doors 

8. other_ 

Part 2. We would now like you to tell us about some of vour activities. 


14. Where do you keep: 


a. fresh fruits 

1. on counter/table 

2. in cabinet 

3. in refrigerator 

4. other_ 

5. don’t usually have 


b. fresh vegetables 

1. on counter/table 

2. in cabinet 

3. in refrigerator 

4. other_ 

5. don’t usually have 


15. In what containers do you store 


16. In 


17. In 


Raw fruits? 

Covered? 

Raw vegetables? 

Covered? 

what containers do you store 


Cereals? 

Covered? 

Pastas? 

Covered? 


what containers do you store meats? Covered? 


BIO 














18. Where do you prepare foods? (check all that apply) 


1. kitchen counter 

yes 

no 

2. kitchen table 

yes 

no 

3. kitchen sink 

yes 

no 

4. chopping board 

yes 

no 

5. other 




19. Do you wash your hands before preparing the food? 

1. yes 1. always 

2. no 2. usually 

3. sometimes 

4. seldom 

20. Do you wash your hands before serving the food? 

1. yes 1. always 

2. no 2. usually 

3. sometimes 

4. seldom 


21. Do you wash the food preparation surface.... 


a. before food preparation 

1. yes 

2. no 


b. after food preparation 

1. yes 

2. no 


22. How do you wash plates and glasses? 


1. by hand 

2. dishwasher 

3. use throw aways/paper plates 

4. other_ 


23. How do you dry plates and glasses? 1. air dry 

2. cloth towel 

3. paper towel 

4. dishwasher 

5. other_ 


Bll 





24. What type of cookware (pots and pans) do you use? (check all that apply) 

1. stainless 

2. aluminum 

3. cast iron 

4. glass 

5. ceramic/pottery 

6. plastic 

7. other_ 


25. How do you wash cookware and utensils? 

1. by hand 

2. dishwasher 

3. other_ 


26. How do you dry cookware and utensils? 

1. air dry 

2. cloth (dish) towel 

3. paper towel 

4. dishwasher 

5. other_ 

27. If you use cloth dish towels- 


How often are they washed 

1. as needed 

2. more than once a week 

3. once a week 

4. less than once a week 
9. don’t know 


Are they also used as 

1. hand towels 

2. face towels 

3. to dry counters 

4. other_ 

9. don’t know 


Answer by Observation 

1. Cleanliness of house 

1. clean 2. somewhat clean 

3. dirty 

2. Cleanliness of child 

1. clean 2. somewhat clean 

3. dirty 


B12 








3. Does the child fist his/her food when handling/eating? 

1. yes 

2. no 

Thank you for your help. Do you have any questions at this time? 


B13 


































































































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